Natter’s Notes

Brown Rot vs Bacterial Blight/Canker

Jean R. Natter, OSU Master Gardener

Fig 1:
To verify a diagnosis of bacterial blight/canker, expose the cambium adjacent to, and below, the ooze. (Image: PNW Disease Handbook)

Two problems common to many fruiting and ornamental Prunus species are bacterial flower blight which often progresses into bacterial canker, and brown rot blossom blight and fruit rot.

Both diseases begin with very similar signs and symptoms. Flowers brown earlier than normal and collapse; the infection sometimes continues onto the attached twigs, where the affected leaves dry and cling to the branch; then, too, gumming or ooze may appear. Both diseases may kill branches, eventually the tree.

So, if you’ve been stumped now and then as to the correct diagnosis—brown rot versus bacterial blight – be heartened by the words of Jay Pscheidt, co-author of the PNW Disease Management Handbook: “Symptoms of the two will initially look the same. The big difference will be the development of signs – brown rot spores that give it that dull sort of gray coloration. So, if it has spores, it is for sure brown rot but, if they do not develop, we can’t really say for sure which it might be.” (Ed. comment: Ugh.)

A diagnostic option

As you know, MGs begin by obtaining a thorough history from clients. Another critical part of a successful inquiry is to examine suitable samples or images of much more than just one leaf.

Professional plant detectives visit sites where the troubled plants live; MGs don’t. Determining an accurate diagnosis is difficult, sometimes impossible while confined to an office.

But we must make every effort to resolve the issue before hand. One option is to pass the inquiry to the next shift or two via a Referral Form, another is to contact another of the metro MG offices during our shift.

Although MGs seldom submit affected tissues to the OSU Plant Clinic for diagnosis, we can do so. Insect ID is free; disease ID typically requires a fee. But, before submitting any sample from your MG Office, consult with one of the following persons: for Clackamas County: Jane Collier; for Multnomah and Washington Counties: Jean Natter.

Factors in both diseases

– Cold wet weather for Bacterial Blight; warm moist weather for Brown Rot. (This spring was perfect for brown rot.)

– Stressed trees are more susceptible.

– Some cultivars have tolerance while others are very susceptible

Fig 2:
A verification of brown rot may have to wait until signs of fungal sporulation appear on affected tissues, among them fruits. (Image: Jean R. Natter)

Cultural management of brown rot

– Remove and destroy infected twigs and branches in summer.

– Remove and destroy all affected fruit all dropped fruits as well as mummies that cling to the tree; don’t compost.

– Avoid wounding fruit at harvest and cool it immediately.

Chemical management of brown rot

– Apply fungicide during bloom; PNW Disease Handbook lists possible home gardener products.

– Realize that a product suited for application to ornamental flowering trees may be prohibited for fruiting trees.

Cultural management of bacterial flower blight

– Prune out affected tissues during dry weather; avoid the rainy months when bacteria may easily enter healthy tissues via leaf scars, the site of a mechanical injury, and/or pruning wounds.

– Disinfect pruners between trees with a 30-minute soak in 70% alcohol or in 10 percent bleach (9 parts water with one part of bleach)

– Consider replacing severely affected tree(s) with a tolerant kind. “Prunus sargentii ‘Rancho’ and P. yedoenis ‘Akebono’ appear to have some resistance. ‘Kwanzan’ cherries appear to be resistant when mature but not when young.” (

Chemical management of bacterial flower blight

– No chemicals are listed for use by home gardeners.

– Client could hire a Certified Arborist to spray. It’s helpful to request on-site evaluations from 3 or more Certified Arborists. (Use zip code to search for nearby Certified Arborists at

– Use of copper is discouraged because of bacterial resistance problems, also that it may increase disease intensity.


Bacterial Flower Blight and Canker:

— PNW Disease Handbook:

— Bacterial canker –

Brown Rot Blossom Blight and Fruit Rot:

— PNW Disease Handbook:

—  Brown rot –

PDF Version Brown Rot vs Bacterial Blight

Two bees on lavendar plants“The hum of bees is the voice of the garden.”
–  Elizabeth Lawrence

Bees and Master Gardeners are abuzz as summer approaches.  Master Gardeners are busy volunteering throughout the tri-county metro region.  Many opportunities are available for MGs to learn, educate, and serve the gardening public.

Master Gardeners at Area Farmers Markets

Late spring harvests are filling neighborhood Farmer’s Markets as the first day of summer approaches and metro-area Master Gardeners stand by at MG clinic booths to answer market goer’s gardening questions.

These festive community events are a wonderful opportunity for MGs to educate beginning and advanced gardeners alike with proven gardening practices.  In addition, those volunteering have the chance to pick-up fresh-from-the-field produce, dine on market cuisine, and listen to cheerful tunes.

Schedule a shift via CERVIS for a great summer volunteer experience.  Don’t despair if your favorite market schedule appears full.  Check back often, as schedules change and openings arise throughout the summer – sign-up on the waiting list for a particular shift.  Let a clinic coordinator know you if you are willing to serve as a substitute for last minute cancellations at your favorite market.  The following markets currently have openings: Beaverton, Lents, Gresham, Hillsdale, Sherwood, and Tigard.

Two Master Gardeners, one sitting, one standing, to greet customers at a Master Gardener question and answer table at Farmers Market.
Photo courtesy of Angela DeHaven

Summer Farmer’s Markets
Beaverton – Gresham – Hillsdale – King – Lake Oswego – Lents – Milwaukie
Oregon City – Sherwood – Tigard

Two Master Gardeners in Master Gardener office talking to a client.MG Office Helplines are a Buzzin!

The Master Gardener Office helplines are buzzin’ with an interesting assortment of questions from home gardeners.  “Why do my grape leaves look bubbled and blistered? Will it affect my harvest?”, “Can you recommend tomato varieties resistant to Verticillium wilt?”, “What’s wrong with my small Douglas Fir tree? I notice the top branches are somewhat curled and, upon a closer look, the branches are covered with small, white tufts. What is this?”

The variety of inquiries brings great opportunities to practice your diagnostic skills, expand your garden knowledge and that of the home gardeners you assist.  Join the fun researching and collaborating with your fellow MGs, while educating others.  You will be surprised by the wealth of information you will learn!   Sign-up on CERVIS.

Master Gardener presenting gardening talk to audience.New Workshop!
Hone Your Skills as a Garden Educator!

Are you interested in making gardening presentations to the public as part of the metro-area Master Gardener Speaker’s Guild?  Do you want to refine your presentation skills?

Get ready to present interesting, engaging and impactful presentations in this all-day workshop. Hone your skills as a stand-up trainer.  Plan to attend this all-day session, Saturday, June 15, at the Washington County Extension office in Beaverton, from 9am to 3:30pm.

Workshop taught by Sandy Japely, OSU Master Gardener and professional trainer. Pre-registration required. Learn more about this workshop and register today on CERVIS

Beginning Vegetable Gardening Workshop – a few spaces remain.  Do you have your eye on one of the other remaining workshops that are full? Be sure to add your name to the waiting list as openings do arise.

Blue Lake Discovery Garden

Girl digging with plastic shovel in worm bin.A lovely place to volunteer in the summer is the Blue Lake Discovery Garden.  Registration is now open!

For four Saturdays this summer, Blue Lake Natural Discovery Garden will be offering free, family-friendly, education programming at the Discovery Garden!

During activity times, visitors of all ages—but especially younger kids—can participate in fun, hands-on learning. Master Gardeners assist visitors with various nature crafts, like critter coloring, seed planting, garden bingo scavenger hunts, and garden education for all ages..

For five Tuesdays this summer, garden volunteer service parties at the Discovery Garden have been scheduled. During these volunteer service parties we will be doing a variety of gardening tasks. Plus, occasionally planting and rebuilding sections of the garden.

Shift hours for all events are 10am until 2pm. Volunteer hours are for “Partner” credit.

Sign-up to volunteer for one of these valuable volunteer service activities on CERVIS.

Expand Your Horticultural Knowledge in the Garden!

Our metro-area Chapter-sponsored Demonstration and Education Gardens are fantastic places to expand your gardening knowledge with hands-on learning, plus the opportunity to educate the visiting public.  The Chapter gardens display best garden practices, provide teachable moments for gardening challenges, undertake citizen science projects, and grow thousands of pounds of nutritious fruits and vegetables donated to area food banks!  Drop-in and take part in these valuable Chapter projects. Contact a garden coordinator for volunteer hours.

Master Gardeners showing group of school students garden at Oregon Trail Garden.
Master Gardeners hosting visitors at End of the Oregon Trail Garden

Clackamas County has these great hands-on volunteer opportunities:

  • End of the Oregon Trail Interpretive Center – Check in to see how you can join the fun tending the garden and (for those interested) hosting school tours.
    Sharon Andrews 503-577-7493
  • Hopkins Demonstration Forest – Tend native plantscapes – in a beautiful forest setting!
    Frank Wille
  • ‘Grow-An-Extra-Row and Learning Garden’ Project at Clackamas Community College – Make a difference growing food for those experiencing food insecurity.
    Nancy Muir 503-789-6970

Master Gardener wearing hat, holds a large head of cauliflower.
Photo courtesy of John Jordan

Multnomah County Master Gardener’s Community Demonstration Garden in Southeast Portland. There is lots to do and lots to learn in the established edible garden and in the newly expanded annex garden which includes edibles, herbs, native plants and ornamentals!

Heidi Nichols at  or 503-826-5851
Nancy Fine at or

Master Gardeners harvest peas at Jenkins Estate Garden, in front of sign that says 'Give Peas a Chance'

Washington County Master Gardeners have two wonderful gardens at which to discover and learn!

  • Learning Garden at Jenkins Estate – Lend a hand in this beautiful landscape.
    Sandy Japely
    at 503-531-8482.
  • Education Garden at PCC Rock Creek – be part of the exciting beginnings of a fabulous community garden partnership!
    Sue Ryburn at


Fall Recertification

Save the date for our annual Fall Recertification training.  This year we will gather at Clackamas Community College on Saturday, November 9th, 8am to 4pm.

This annual event is a daylong continuing education opportunity.  Earn 6 hours of continuing education credit by attending.  More details to come in the July/August issue of our metro MG newsletter.

Fall Recertification also gives us the opportunity to congratulate the new class of Master Gardener interns as they step-up to Perennial status after completing their volunteer requirements.  We will present 2019 Interns with their OSU Extension Service Master Gardener badges and a big-shout out for successfully completing the program.  2019 Interns are welcome to attend the full day of training – which will count toward your continuing education/recertification hours for 2020.

Image from the Oregon Department of Agriculture of 10 invasive insects
Photo credit: Oregon Department of Agriculture (CC BY-NC_ND 2.0)

“Let’s Talk Invasive Insects!” – Advanced Training Webinar

‘Invasive Insects’ are an important and timely subject for the next online Advanced Training Webinars for Master Gardeners sponsored by Oregon State University Extension.  This live webinar is scheduled for Friday, June 28th, 10am.

“Did you know that we get about 9 new exotic invertebrate species established in Oregon every year? Want to know what you can do to reduce the impact of invasive species in Oregon? Join Joshua Vlach, entomologist with the Oregon Department of Agriculture, for a presentation on the risks associated with invasive species, the pathways that bring them here, their impacts, and what you can do to reduce the chance of bringing and spreading pests in Oregon. Specific resources for reporting suspected invasive species will be shared.”

Details & pre-registration info:

The Advanced Training Webinars each count for 1-hour continuing garden education/recertification credit.  A wonderful way to expand your gardening knowledge in the comfort of your own home or sitting in a lovely garden watching on the electronic device of your choice.

Can’t make the webinar date?  No worries!  Recordings of webinars are posted a few days after the live webinar.  Follow this link:

Photo credit: Oregon Department of Agriculture (CC BY-NC_ND 2.0)

Log Your Volunteer Hours

Thank you for your passion, energy and volunteer service educating the gardening public.  We want to be sure to have a record of all your efforts.  Here is the link you need, to download the form, to log your volunteer hours.  Even hours recorded on CERVIS need to also be recorded on your individual Volunteer Log Sheet.  Log sheets are due by October 1, 2019.

MG Nuts and Bolts

Need a refresher on how to maintain your OSU Extension Master Gardener certification?  All the nuts and bolts can be found here!

OSU Master Gardener Bob Falconer standing next to a field of blooming Phacelia.Metro-area Master Gardener Featured on PolliNation Podcast!

Metro-area Master Gardener Bob Falconer was recently featured on the PolliNation podcast.  Bob shares how to establish magnificent strips of pollinator attracting Phacelia and clover.  Check it out!

Three Cheers to Metro-area Chapters!

Congrats to the Clackamas, Multnomah and Washington Co. Chapters for hosting three successful fundraising events this spring!  The Wash. Co. GardenFest, Clack. Co. Spring Garden Fair, and Mult. Co. Incredible Edibles Plant Sale were grand events, with quality plants galore to fill many a gardener’s wish lists.

Beyond the funds raised, each Chapter also focused time on educating home gardeners with reliable gardening advice.

Congrats to all who volunteered and supported the many facets of executing these amazing fundraisers!

Master Gardener watering plants at GardenFest plant sale

Master Gardener wearing hat and safety vest, smiling waiting to assist customers loading plants from plant sale.

Customer surveying plants for sale on tables at GardenFest plant sale, in greenhouse.

Spring Garden Fair

Smiling Master Gardener volunteer at raffle table at Spring Garden Fair.
Spring Garden Fair Photos courtesy of Trish Basler

4 Master Gardener volunteers sit around table, taking a break from activities at the Spring Garden Fair.

Raffle table and Master Gardener volunteer.

Incredible Edibles Plant Sale

Master Gardener holding to cardboard boxes full of donated plant starts from the Incredible Edibles Plant Sale.

Smiling Incredible Edibles Plant Sale customer holding two cardboard trays filled with vegetable plant starts.

Two customers at the Incredible Edibles Plant Sale each holding a cardboard tray of vegetable and herb plant starts.

Natter’s Notes

Noctua pronuba, the Winter Cutworm

Jean R. Natter, OSU Master Gardener

Fig 1: Common mullein, Verbascum thapsus, with numerous holes, most likely caused by the winter cutworm. (J. R. Natter; 2019-04-14)

Winter cutworms, also known as Large Yellow Underwings, were first identified in Oregon about 2001. Since then, they have raised a ruckus in home gardens, lawns, pastures, and agricultural fields during the winter. The larvae (caterpillars) feed on a wide array of plants at night, whenever the air temperature is 40F or more. So, it’s critical that the damage is differentiated from that of slugs and snails which, by the way, don’t always leave a slime trail.

ID characteristics

Both the adult and larvae are seen in several color forms. Among the adults (moths), the wing coloration ranges from light tan to quite dark brown. But certain characteristics are constant, among them the 2 dark, kidney-shaped spots on each forewing.

To ID the larvae (caterpillars), look for a brown, inverted-Y on a light-colored head capsule. And, along each side of the body, you’ll see a row of dark dashes, each one underlined with a slightly shorter, light colored dash. Newly molted caterpillars are bright green. And, as is usual for Lepidoptera, the larvae will also have prolegs and 3 pair of true legs.

Life cycle

Fig 2: Newly molted winter cutworm, 2 inches long (J R. Natter; 2010-04)

During the growing season, the adults rest in the shelter of leaves on low-growing plants. Now and then, it’s likely you’ll flush one out while working in the garden during the summer.

The flash of orange on each hind wing of a brown moth is an easy field ID character. (See

The life cycle follows complete metamorphosis. The several hundred eggs are laid in large patches on the host plant, arranged in neat side-by-side rows. Larvae (caterpillars) hatch in 2 to 4 weeks. They’ll feed in the fall and continue through the winter, at night, whenever the temperatures are above 40F. During the day, the larvae rest just under the soil surface, quite close to the stem of the victimized plant.

Because caterpillars are chewing pests, plant parts disappear. Winter cutworms commonly align with leaf edges and eat inward, creating larges scallops. Or they may chow down somewhere within the leaf blade.

The caterpillars pupate in the soil. Likely you’ll find a number of them as you prepare your flower and veggie beds this spring. A fun project is to rear out the pupae to verify which particular caterpillar species you have.

To rear a pupa, place it in clear container and cover with a breathable lid, perhaps paper toweling held in place with a rubber band. Set the container somewhere you’ll see it often, but not in the sun, then wait for the adult to emerge. Adult moths are always easier to ID than are pupal cases you find in soil.

Common victims

Favored host plants are numerous, among them flowers and vegetables; Pacific coast iris; and the great common mullein, Verbascum thapsus, the latter considered a weed here in Oregon. During 2015, they specialized in “mowing” grasses at their bases.


Because damage occurs during winter, be certain to differentiate damage from that caused by slugs and snails which, by the way, don’t always leave a slime trail. Then, too, before you suggest treatment, determine if damage is current and possibly ongoing. Or is it old damage? In that case, the pest is long gone.


The PNW Insect Management Handbook discusses home garden management of caterpillars in the section Horticultural, Landscape, and Ornamental Crops: Common Landscape Pests.

Take your choice of physical methods, among them to handpick; feed to the birds, drop into a nearby spider web; flick into soapy water; cut in half or stomp. Bacillus thuringiensis (Bt) is an organic ingredient useful against caterpillars on both ornamental and edible plants; always apply according to label directions.


  1. Large Yellow Underwing A New Cutworm in Idaho includes images of several very similar species, most of which are more common in agricultural sites than in home gardens;
  2. Winter Cutworm: A New Pest Threat in Oregon contains close-up views of the larvae [page 3] as well as chemical recommendations for both home and commercial users;
  3. Large Yellow Underwing moth and cutworm caterpillar, Noctua pronuba has excellent images of eggs, larvae, pupae, and adults;

PDF Version Noctua pronuba

By Margaret Bayne, OSU Extension Staff-retired, OSU Master Gardener

May 2019

Photo: Lynn Ketchum, OSU

Liver, colon cancer cells thwarted by compounds derived from hops. (Adrian Gombart, via Steve Lundeberg, OSU)

Sticky science: Evolution of spider webs.  “The eight-legged weavers have been hunting insects for almost 400 million years, flaunting their long history in a rich array of architectures. Scientists are still figuring out the taxonomy of them all.” (Lindzi Wessel,

Alien bird species can help native plants move around, say surprised scientists. (GrrlScientist,

A quest for Bumblebee nests: The missing link. (Amanda Liczner, PhD Candidate, York University, via

Stem girdling roots – Abiotic factors in the landscape and garden.  Watch the video! (Virginia Cooperative Extension, via Youtube)

Beauty is in the nose of the beholder.  “It’s no surprise that a flower releases scent to attract a pollinator, but why would it do it hours before the pollinator is around? New research finds scent can have more than one job.” (Alun Salt, botanyone)

The significance of Cherry blossoms in Japanese art & culture. (Kelly Richman-Abdou,

A lawn is better than fertilizer for growing healthy blueberries. (Blog, Frontiers Science News)

Beware of sleeping queen bumblebees underfoot this spring.  “Scientists at Queen Mary University of London have discovered a never before reported behaviour of queen bumblebees.” (Queens Mary University of London, via

Using arborist wood chips as landscape mulch. (Dr. Linda Chalker–Scott, WSU)

Plant researchers are providing new insights into basic cell division in plants. (Martin-Luther University Hall-Wittenberg via

Understanding the mysteries of plant diseases: Prevention, Control and Cure (Part 3 of 3 in this blog series.) (Jim Downer via

Pretty sly for a whitefily– “One of the world’s worst agricultural pests corrupts the alarm signals of plants, disarming those that otherwise might prepare for an assault.” (Ed Yong,

Life in a cubic foot of a lawn. (Charley Eiseman,

Photo: WSU

Great pruning & training resources for fruit trees. (Treefruit, WSU)

How trees and turnips grow fatter – “Researchers unlock the secrets of radial growth… Botanists have identified key regulatory networks controlling how plants grow ‘outwards,’ which could help us to grow trees to be more efficient carbon sinks and increase vegetable crop yields.” (University of Cambridge via

Something is rapidly killing young apple trees in North American orchards and the Scientists are stumped. (Erik Stokstad,

Watch this great Ted Talk! “Ew to awe: Your view of bugs may never be the same.” (Danae Wolfe via

Cornmeal and corn gluten meal applications in gardens and landscapes. (Dr. Linda Chalker-Scott, WSU)

Check out these amazing illustrations of the nervous system of a honeybee. (Eric Keller,

Plant defenses against them drive diversity in tropical rainforest.  “Researchers have been baffled by tropical rainforest diversity for over a century; 650 different tree species can exist in an area covering two football fields, yet similar species never grow next to each other. It seems like its good to be different than your neighbors, but why?” (U of Utah)

Salal with thrip damage, Photo: Ask an Expert

It’s not Azalea Lacebug damage!  Find out what’s really happening to Salal at the coast. (Ask an Expert, OSU)

Fungi fight plants. These symbiotes are also sometimes screens when it comes to establishing plant ranges.” (Staff,

Compound of berries and leaves of American beautyberry, Callicarpa Americana, show potential as repellents against mosquitoes and, now, some ticks. (Luis Pons,

Antennal sensors allow hawkmoths to make quick moves. “All insects use vision to control their position in the air when they fly, but they also integrate information from other senses. Biologists have now shown how hawkmoths use mechanosensors in their antennae to control fast flight maneuvers.” (Lund University, via

Mosquito Hawk? Skeeter eater? Giant Mosquito? No, No, and No! Learn about Crane Flies. (Leslie Mertz,

PDF Version May 2019

“It was such a pleasure to sink one’s hands into the warm earth, to feel at one’s fingertips the possibilities of the new season.”
Kate Morton

The Merry Month of May!

OSU Master Gardener volunteer opportunities in the metro-area flourish in the month of May as the gardening season begins in earnest!  The Master Gardener helpline offices are abuzz with lots of inquiries from home gardeners.  The Farmer’s Market season is kicking off and there is a flurry of activity and need for eager volunteers at our supporting Chapter’s demonstration gardens!  There are also new learning opportunities with our Master Gardener hands-on workshops and mini-classes.  Learn all the details…

2019 Farmer’s Market Season Begins!

An early start to the Master Gardeners Farmer’s Market season, a chilly morning in April at the Hollywood Farmer’s Market

Master Gardener Clinic Booths are popping up at Farmer’s Markets around the tri-county area. Master Gardeners are answering home gardener’s questions at the following markets in May.

Beaverton – Gresham – Hillsdale – King – Lake Oswego

Milwaukie – Oregon City – Sherwood – Tigard

Sign up for a shift on CERVIS or contact the clinic coordinator, Marcia or Janet for assistance signing up.

Master Gardener Office Helplines

It’s amazing what you can learn educating others and that opportunity is there for all who volunteer at the Master Gardener office helplines!  Research and collaborate with fellow MGs while educating the gardening public.   Sign-up on CERVIS or contact a phone coordinator.

Clackamas County, Janet Hohman,
Multnomah County, Janet Hohman,
Washington County, Jenifer Halter,

Keep an eye out!  Special Volunteer Events.

Special volunteer events arise throughout the season so be sure to watch for email announcements from MG program staff or postings on CERVIS to snag a slot at one of the many special volunteer opportunities.

Speaker’s Guild Mini-Class

Are you interested in becoming a presenter for the Master Gardeners Speakers Guild or are you already a Speaker’s Guild presenter and you want to brush-up your presentation skills?

Our 3 Master Gardener Speaker’s Guild coordinators are presenting 2 mini-classes in May to support those interested in becoming a Speaker’s Guild presenter.

Friday, May 17th @ the Happy Valley Library, Happy Valley, 4pm to 5:45pm

Saturday, May 18th @ the Holgate Library, Portland, 3pm to 5pm

These mini-class will focus on tips and tricks for giving engaging presentations that offer quality garden information, while creating a welcoming, fun experience for your audience.  Learn how you can branch out as a garden educator sharing your passion for gardening and the proven gardening techniques you have acquired through your Master Gardener training.  Meet our 3 Master Gardener Speaker’s Guild coordinators and learn about the resources and support available for you as part of this fun, rewarding volunteer opportunity.

Register for a Speaker’s Guild Mini-Class on CERVIS.  Look for the ‘Speaker’s Guild Mini-Class’, pick your preferred date and register.

Speakers Guild

The metro-area Master Gardener’s Speakers Guild members make presentations on a variety of gardening topics to community groups throughout the metro-area.  Requests for presentations come from garden clubs, civic groups, libraries, schools and other organizations.  For some topics, we have prepared PowerPoint presentations and for other requests new programs are developed.  Through the Guild, you will find opportunities to develop and/or deliver programs in subjects that interest you.  Support is offered to those new to public speaking.  Volunteers can also shadow presenters that are more experienced.  You get to choose presentation opportunities that appeal to you (e.g. date, location, small groups, large groups, with PowerPoint presentation or simply a demo or talk).  The Speakers Guild is a rewarding Master Gardener activity where you can dispense sound gardening information to the gardening public.

*Time spent at these Speaker’s Guild mini-class can be counted as ‘Program’ volunteer hours.  Perennial Master Gardeners can count the class time as EITHER ‘Program’ volunteer service hours or ‘continuing garden education’ hours.

Hands-on Workshop Openings!

A few slots remain for our 2019 training workshops.  Sign-up on CERVIS, plus find details about the workshops, including location.  These workshops are a great way to expand your gardening know-how in an interactive, hands-on environment with expert instructors.

The following workshops still have openings as of the composition of this newsletter.

  • May 10 – Beginning Vegetable Gardening
  • May 31 – Summer Fruit Tree Care
  • June 1 – Summer Fruit Tree Care
  • June 8 – Beginning Vegetable Gardening
  • June 15 – Plant Propagation

Note: If you are interested in a workshop that is full, add your name to the waiting list – as openings often occur.

Another Great Series of Advanced Training Webinars

The 2019 Master Gardener Advanced Training Webinar Series is off to a great start.  Here are the next 2 scheduled webinars:

Coddling moth infested apple. Photo: Michael Bush, WA State University Extension

Project Happy Apples: Reducing Codling Moth Damage in Backyard Orchards
Presented by Amy Jo Detweiler (OSU Extension)
May 21, 10am PT
Details & pre-registration info:

“First Look” Reading a Pesticide Label to Protect Bees
Presented by Matthew Bucy (OSU Undergraduate Honors student)
May 30, 11am PT
Details & pre-registration info:

If you are unable to participate in the webinar live, be sure to check back as recordings are made available a couple weeks following the live event.

2019 Webinar recordings:

2018 Webinar recordings:

Frequently Asked Questions…

How do I log my volunteer hours?
To maintain an ‘active’ Master Gardener status or to complete your Master Gardener training you need to log your volunteer and education hours on a 2019 Volunteer log sheet and submit them to the MG program office by October 1, 2019.

You can download the log sheets at the Metro MG Program Volunteer Portal.  Just click the on the 2019 Volunteer Log Sheets link.  There you can choose between a Word Doc or Excel sheet.

Does CERVIS track my hours?  Yes, CERVIS does track your volunteer hours, BUT you need to transfer those hours onto your Volunteer Log sheet and submit them along with your other volunteer hours.  To access your history log into CERVIS and go to “Report Management”, then click “View or Print Volunteer Activity History” and transfer those hours to your log sheet.

What hours do I log?

  • Interns – log your volunteer hours and the Hands-on workshops that you attended
  • Perennials – log your volunteer hours and the continuing garden education/recertification hours you attended

Then simply submit all volunteer and education hours to the MG program office by October 1, 2019.

The Plant Sale Trifecta Continues!

Megan displaying a plant for sale at Gardenfest 2019

The Washington Co. Master Gardeners had a hugely successful fundraising plant sale on April 27th.  All who attended the inaugural, 2019 Gardenfest found glorious plant offerings, valuable gardening information to ensure a successful garden, and happy gardeners all around!  Hats off to all who made Gardenfest a wonderful success!

The plant sale trifecta continues, so be sure to join in the upcoming Chapter festivities…

Spring Garden Fair, Saturday, May 4th , 9am to 5pm, and Sunday, May  5th, 9am to 4pm
Cruise on over to the iconic Spring Garden Fair to find a treasure trove of perennials, annuals, shrubs, trees, small fruiting plants, veggies, herbs, garden tools, and garden art!  10-minute University garden classes, pH soil testing, kids activities, a raffle, and more!  Clackamas County Event Center, Canby

Incredible Edibles Plant Sale, Saturday, May 11th, 10am to 3pm, a community celebration for home-grown goodness – organic veggie, fruit and herb starts will get you growing!  Plant. Grow. Eat. Workshops, music, kids activities, a raffle and more! 1624 NE Hancock Street, Portland.

Dig-in!  Lend a Hand and Learn at a Demonstration Garden!

Hands-on learning in any of our ‘Partner’ demonstration gardens is rewarding.  Each garden offers unique active, relevant, learning opportunities.  Contact a coordinator and dig in!

Clackamas County has the following great hands-on volunteer opportunities:

  • End of the Oregon Trail Interpretive Center – Check in to see how you can join the fun!  Contact: Sharon Andrews 503-577-7493
  • Hopkins Demonstration Forest – Tend native plantscapes – in a beautiful forest setting! Contact: Frank Wille 503-342-6699,
  • Grow-An-Extra-Row and Learning Garden’ Project at Clackamas Community College – Help to grow food for those experiencing food insecurity. Contact: Nancy Muir 503-789-6970

Multnomah County Master Gardeners have over 1.5 acres of garden where you can learn and grow:

MGs at the Jenkins Estate Garden Give Peas a Chance

Washington County Master Gardeners have two wonderful demonstration garden locations:

  • Learning Garden at Jenkins Estate – Lend a hand in this beautiful landscape. Contact: Marilyn Berti, MG contact: Marilyn Berti
  • Education Garden at PCC Rock Creek – be part of the exciting beginnings of a fabulous community garden partnership! Contact: Sue Ryburn at

Woodland Wildlife Field Workshop

Our Clackamas County Extension Forestry team is presenting a Woodland Wildlife Field Workshop, on Saturday, May 18. Spend an informative day in the beautiful Hopkins Demonstration Forest.  This workshop will be led by two great wildlife biologists: Fran Cafferata-Coe, certified wildlife biologist with extensive consulting experience in applied wildlife biology on working forests; and Jimmy Taylor, research wildlife biologist for the USDA Animal and Plant Health Inspection Service (APHIS) in Corvallis.

Register now and learn more here!

By Margaret Bayne, OSU Extension Staff-retired, OSU Master Gardener

April 2019

Photo: University Connecticut

Corn gluten meal did not prevent weeds from germinating in OSU study. (Tom Cook, OSU)

A gardener’s primer to cold hardiness, part 2 (see part 1 in last month’s MG newsletter-Horticultural Updates) (Dr. Linda Chalker-Scott, WSU)

Insect Apocalypse?The underlying science does not indicate that a global “insect apocalypse” is anywhere near imminent.”  Read what the Entomological Society says about the recent media reports of the demise of insects. (

You are what you eat: A color-changing insect modifies diet to become distasteful. “Lanternflies change diet and color to become distasteful and signal distastefulness.”

Seed Oddities: Vivipary-The type of vivipary discussed is quite rare, occurring in only a handful of species and prevalent in a select number of environments. (

Individual lichens can have up to three fungiaccording to new research from an international team of researchers. This evidence provides new insight into another recent discovery that showed lichen are made up of more than a single fungus and alga, overturning the prevailing theory of more than 150 years.” (University of Alberta, via

Extracellular DNA, in plant health and hardship. “…in plants, there’s no blood or specialized immune cells to retaliate against pathogens.”  Learn now plants ensure a speedy return to health. (Sophia Swartz,

Winter leaf Marcescence– learn why some trees hold onto last year’s leaves longer in the spring than other trees. (Joey Williamson, Clemson U)

Arborvitae stands tall as a low-maintenance hedge. (Neil Bell, via Kym Pokorny, OSU)

3-D Scans Reveal Caterpillars Turning Into Butterflies-Amazing video! (Ed Yong,

Feel the Heat: Temperature and Germination- “Thinking of it this way, seeds and germination are just like Goldilocks and her porridge – there’s too hot, too cold, and “just” right.  Seeds are the same way – there’s a “just right” temperature for germination. The seeds of each species has a different optimal temperature for germination with a range of minimum and maximum temperatures for the process.”  Learn more from an expert. (John Porter,

How the humble marigold outsmarts a devastating tomato pest.  “Researchers carried out a study to prove what gardeners around the world have known for generations — marigolds repel tomato whiteflies.” (Newcastle University, via

Infographic: Plants Deploy Exosomes to Stop Alien Invaders.  “A growing branch of research on how plants use exosomes to interact with their environment is opening up a new field of plant biology.” (Amanda Keener,

Desert bacteria give plants an edge over high salinity soils. (Sterlingadmin,

Retreating ice exposes Arctic landscape unseen for 120,000 years. (Stephanie Pappas,

Greener childhood associated with happier adulthood. (Johnathan Lambert,

Photo: NPIC – Oregon State University

Garden use of treated lumber.This fact sheet explains the most widely used method for treating wood, examines the possible risks from gardening uses of treated lumber, and makes recommendations for reducing any such risks.” (Richard Stehouwer, Penn State U)

A tasty Florida butterfly turns sour. “A 15-year study by entomologists found that, when living apart from the unsavory bug it mimics, the viceroy butterfly becomes yucky, making biologists rethink old theories about animal mimicry.” (University of Arizona, via

Inside the Spittlebug’s bubble homeThose foamy eruptions on garden plants protect a slow and steady sap drinker that is growing into a froghopper. But it has to stick its hind end out to breathe.” (James Gorman,

Weird new Tarantula species discovered with bizarre “horn” on its back. “Details of a new tarantula previously unknown to science have been revealed by researchers working in Angola. The spider has a very peculiar feature, unlike any other related species we have encountered so far.” (Alfredo Carpineti,

Bizarre Video Shows A Frozen Tree Melting From The Inside- “a coat of ice has slightly peeled away from the trunk and branches, allowing a steady stream of water to trickle down the bark under the icy top layer as it melts.”  Cool! (Tom Hale,

Fruit flies don’t need sleep like other animals to survive, study suggests. (Kristy Hamilton,

Honeybees’ waggle dance no longer useful in some cultivated landscapes. (R. I’Anson Price, et al; via Johannes Gutenburg Universitat, Mainz)

Understanding mysteries of plant diseases: Diagnosis and Detection (Part 2 of 3 in this blog series) (Jim Downer,

Rediscovering Wallace’s Giant Bee: In Search Of Raja Ofu, The King Of Bees (Clay Bolt, Lost Species News via

Snowdrop basics.  “The sight of snowdrop shoots poking up through snow-covered ground is one of the first signs that spring is near. It was once thought that their leaves were thermogenic, producing their own heat in order to melt through the snow. However, it is more likely a thermal effect of sunlight heating the tips of the leaves warmer than the surrounding snow.” (Linda Hagen,

Photo: Oregon State University

Planting a garden soon?  Find out which vegetables were hits or misses from OSU’s 2017 research. (Brooke Edmunds, et al; OSU)

Tyrannosaurus rex ate meat but also accidentally planted fruit.  “T-Rex is famous for being a deadly carnivore, was likely assisting in the widespread dispersal of fruit seeds. A recent report in New Scientist suggests that T Rex was inadvertently planting fruits across the landscape in its droppings after devouring plant-eating animals.” (Chrissy Sexton,

This beetle bites an ant’s waist and pretends to be it butt.  “It takes an unusual strategy to survive nature’s most destructive swarms.” (Ed Yong,

Insect identification: Experts and guides to ID that bug you found. (

Pollen sleuths: Tracking pesticides in honey bee pollen to their source plant. (Kimberly Stoner, Richard Cowles, and Brian Eitzer,

Genetically modified super-charged Cassava could help stamp out malnourishment in Africa, (Tom Hale,

100-million-year-old amber fossil suggests Mosquitoes carried Malaria when dinosaurs walked the Earth. (Rachel Baxter,

Downy Mildew resistant Impatiens may be available soon! Syngenta to launch IDM-Resistant Impatiens at Spring Trials. (Chris Beytes,

Spring has returned.  The Earth is like a child that knows poems. 
–  Rainer Maria Rilke

Master Gardeners Grow!

Our gardens are bursting forth with color and new growth and the Metro-area Master Gardener program is growing too!  This past month, nearly 190 Master Gardener trainees finished their in-person classes, online modules, and final exam, and they are now venturing out and joining-in to serve as garden educators in the OSU Master Gardener program.

Class of 2019 Master Gardener Interns Dig In!

A warm welcome and congratulations to our 2019 class of Master Gardener Interns.  Now that you have completed the in-person class and final exam, you have the opportunity to dig deeper to expand your gardening knowledge during hands-on workshops and in your role as a volunteer garden educator.  Your volunteer service offers opportunities to learn in an active, hands-on format.  We hope you will try a variety of volunteer opportunities…Master Gardener office or market clinics, Chapter demonstration gardens or one of our many partner events.  Trying a variety of volunteer opportunities will help you to discover the wealth of knowledge available to you as an OSU Master Gardener!  We hope you enjoy your educational journey!

Message to Perennial Master Gardeners

Hearty spring greetings and ‘welcome back’!  As the growing season and the Master Gardener program gets it’s jump-start we look to you for your steadfast dedication to educating the gardening public.  We also rely on you to welcome our new class of Master Gardeners.  Do you remember how you felt during your first volunteer shifts?  Perhaps excited, nervous, apprehensive, unsure?  When you volunteer in the next few months take extra time to welcome and assist Intern Master Gardeners.  Provide a welcoming environment, orient Intern MGs regarding procedures, and guide them towards our OSU information resources.  The Interns are coming fresh from MG training – and so they also have knowledge and experience they can share.  It is an opportunity to learn and support each other.

We look forward to seeing you this gardening season and remain grateful for your continued, generous, dedicated service.  Thank you!

Office Orientations OPEN on CERVIS!

Orientations for Master Gardener office hotlines are open for Interns or Perennial Master Gardeners. Office orientations are a great way to learn or be reacquainted with our 3 metro-area Master Gardener office hotlines.  Openings remain for all three locations: Beaverton, Oregon City and Portland.

Learn more about the ins and outs of answering home gardening questions in the Master Gardener offices.  A Perennial Master Gardener will lead a brief tour of the office, review basic procedures and answer your questions.  Sign-up for office orientations on CERVIS.

The “Volunteer Portal”

Located on our Metro Master Gardeners website the Volunteer Portal leads metro-area Master Gardeners to valuable information. Once there you can read the monthly Metro MG newsletter; review how to maintain your active MG status, sign-up for volunteer shifts on CERVIS, check out the events calendar and more!

Oregon Zoo Education Center Orientations

Photo: courtesy of Metro

Volunteer at the Oregon Zoo Education Center answering gardening questions, while working closely with Metro education specialists. Interact with both adults and children.  Highlights include features for winged wildlife and wise-water use. Master Gardeners provide the Zoo visitors with garden guides on natural gardening, native plantings, and composting (including a live demo on worm bins).

Attendance at one of the orientations is required for all volunteers at the Oregon Zoo.

Sign up for an orientation on CERVIS.

  • Saturday, April 13, 9:30am to 1:30pm
  • Friday, April 19, 10:00am to 2:00pm

Volunteer shifts for the Oregon Zoo Education Center will be made available to those who complete an orientation.  Sign-up will be open following the April 19th orientation.

Workshop Series OPENS for Perennial Master Gardeners!

We have opened the metro-area Master Gardener Hands-on Workshop Series for all current, certified Perennial Master Gardeners!  We have a stellar line-up this year with over 15 workshops.

Perennial Master Gardeners can sign-up for one workshop.  To register for a workshop go to CERVIS.

For Master Gardener Volunteer Educator Interns (Options 1 and 3), if you haven’t already – you can enroll in up to two workshops, which are included in your tuition.  You are required to complete one workshop to complete your Master Gardener training. For Certificate of Home Horticulture students (Option 2), you can enroll in up to three workshops, which are included in your tuition.

IMPORTANT: If you have registered for more than your allotted number of workshops (see paragraph above) please un-register for any above the allowed maximum to allow those who were unable to register for any workshops.

WORKSHOP FULL?  If you find the workshop you are interested in attending is full – be sure to sign-up on the waiting list.

Utmost Thanks to Our Stellar Instructors!

Margaret and Jane teaching Plant Diagnostics class

Our Master Gardener training offers the best in solid research-based horticulture curriculum due to the knowledge and generosity of our instructors!  We extend immense thanks to all of our instructors for educating and inspiring our 2019 Master Gardener trainees and those Master Gardeners who attended training to keep their diagnostic skills sharp.  We are grateful to our instructors for the time they spent preparing, teaching and engaging all who attended the classes.  Thank you!

  • Margaret Bayne
  • Nick Bezzerides
  • Chip Bubl
  • Sally Campbell
  • Jane Collier
  • Claudia Groth
  • Monica Maggio
  • Jean Natter
  • Rachel Suits
  • Ron Spendal
  • Heather Stoven

 Extending Immense Thanks to Our Class Coordinators!

“Wisdom is knowing what to do next; virtue is doing it.”  – David Starr Jordan

Hillsboro MG class coordinators Louise and Marti compile Sustainable Gardening Handbooks

There is no doubt we have a wise and virtuous team of volunteer coordinators for our three Master Gardener training venues!  Our lead volunteer coordinators:  Louise Gomez-Burgess and Marti Farris (Hillsboro class), Cindy Manselle (Oregon City class), and Beven Peters and Rich Becker (Portland class); along with their supportive team of volunteer’s displayed beyond measure dedication that made for a very successful Master Gardener training!

Each volunteer team attended to the biggest and tiniest details to ensure a successful training and a welcoming venue for the new trainees.  Thanks for compiling, hauling, setting up, attending to AV needs, announcing, assisting Interns, spreading out the hospitality table, and cleaning up the last crumb before turning off the lights.  We are grateful for your time, assistance and attentiveness!

Special thanks to Marilyn Frankel and Jane and Mike Collier for lifting and hauling PNW books and supplies across the tri-counties far and wide!

Kudos Metro-area Chapters!

Thank you to the Clackamas, Multnomah and Washington County Chapters for their financial support of the Metro MG training classes.  The facility, hospitality and parking fees would prohibit training happening in such great venues.  Thank you for your constant and generous support of the OSU Metro Master Gardener training program.  Your contributions make such positive and vital difference to the Master Gardener program!

Plant Sales Galore!

Get ready!  April brings the start of our 3 supporting Chapter’s as they roll out a series of three fantastic fundraising plant sales.

Mark your calendars, save the dates and get ready to volunteer and shop-till-you-drop!  These are extremely fun events to attend and most especially fun to serve as a volunteer.  Don’t miss out!

Washington County MG’s Gardenfest Plant Sale – April 27th

A successful fundraising tradition emerges as the Washington Co. Master Gardener’s hold their first annual Gardenfest Plant Sale.  A fundraising plant sale that guides home gardeners in creating beautiful gardens that thrive!  Perennials, shrubs, vegetables, annuals, herbs, and garden tools!  Classes that support successful gardening!  Find ideas that inspire as you tour the Washington Co. Master Gardener’s new Education Garden. PCC Rock Creek Campus, Portland 17705 NW Springville Rd, Portland, OR 97229

Clackamas County MG’s Spring Garden Fair – May 4th and 5th

The iconic Spring Garden Fair will satisfy anyone’s plant lust! Perennials, annuals, natives, ornamentals, veggie, fruit, herbs, garden art and garden supplies!  10-minute University classes, Soil pH testing, New Plant Introductions, fabulous raffle and more! Clackamas County Event Center, Canby.

Volunteer opportunities, see…
For Spring Garden Fair details, see…

Multnomah MG’s Incredible Edibles Sale – May 11th
To volunteer email
Event details

The Incredible Edibles Plant Sale is a community celebration for home-grown goodness – organic veggie, fruit and herb starts will get you growing!  In addition, find a great selection of garden tools, garden art, classes filled with tips and tricks for gardening and cooking up your harvest! Live music! Kids Grow tent! Raffle! Fun for all ages!  1624 NE Hancock Street, Portland

Thumbs Up for 2019 Master Gardener Training!

I love spring anywhere, but if I could choose, I would always greet it in a garden. – Ruth Stout

We know spring is near, despite the wintry precipitation and biting cold, as we welcome a new class of 2019 OSU Master Gardener Interns and gear up for an exciting season educating the home gardener in successful gardening practices! So polish up your OSU Master Gardener badge and get ready for a new slate of MG activities and volunteer opportunities.

It’s time to reach out and engage in the myriad of clinics, projects and special events.  Return to your favorite Master Gardener activity or try something new! Look for opportunities on CERVIS and in upcoming newsletters and emails.

Welcome Class of 2019 Master Gardeners!

A hearty welcome to our 2019 class of Master Gardener Interns!  We are excited to have you joining our program of committed garden educators.  You are over halfway through your training and soon you will be out in the community actively practicing and sharing your newfound knowledge.

Possibilities will abound with a wide-range of volunteer opportunities.  You will hear about the many OSU approved offerings during week #6 of class.  We hope you will dig in, have fun, and share your passion for gardening with fellow MGs and the gardening public.  This is an opportunity to further your garden education and to gain confidence in teaching others how to sustainably and successfully garden.

Key points for 2019 MG Interns:

  • Complete the four required training modules plus the corresponding quizzes, and an additional module of your choice, along with the quiz, by March 31, 2019.
  • Complete the online final exam by March 31, 2019. The exam will be available starting the evening of March 15th. Please, allocate three to five hours to complete this online learning experience.  You can stop and start the exam, and you can complete the exam in multiple sessions (be sure to save your work).  A score of 70 percent or more is required on the test in order to start volunteering at Master Gardener clinic activities (answering the public’s garden questions). You will receive a grade on the exam upon submission via Canvas.  The exam is open book.  Feel free to refer to your online modules, Sustainable Gardening Handbook, and in-class handouts.
  • For best selection, be sure to sign-up for your required Workshop before March 31st. Soon after that date, the Workshop schedule will open to all Master Gardeners and the offerings will fill quickly.
  • Hear about the many volunteer opportunities during Week #6. This will be your opportunity to meet the volunteer coordinators and learn how to sign-up for volunteer activities via CERVIS (our online volunteer system).

Special message to our “Perennial Master Gardeners”

Perennial Master Gardeners, please join-in welcoming and guiding our new class of eager Master Gardener Interns by signing up for shifts at the Master Gardener phone clinics, area farmers markets, and other remote clinics.  We hope to have one Perennial MG per shift scheduled before March 10th – so when trainees sign-up for shifts at the MG training Resource Fair they will have a Perennial MG to be there to support and guide them in their new role as a garden educator.

To sign up for phone, farmer’s markets, and remote clinic shifts go to CERVIS or contact the coordinator.

When signing up for CERVIS be sure to only sign-up for slots labeled “Perennial” or “Perennial/Intern”.  Please do not sign-up in slots labeled “Intern only”

All ‘current’ certified 2019 Perennial Master Gardeners have access to CERVIS.  If you are unable to access CERVIS, please contact Marcia McIntyre   2019 Interns, you will have access to CERVIS on Saturday, March 16th, after the week #6 Resource Fair.

Photo credit: Sterling College

Demystifying Grafted Tomatoes: The Why & How for Gardeners

If you have been curious about grafting tomatoes then catch the next OSU Master Gardener Advanced Training Webinars!  You can take part in this informative webinar, presented by Dr. Cary Rivard, of Kansas State University, on Friday, March 15th, at 11AM.  To register, go to:

If you can’t view the live webinar, a recording will be available a week or so after the live event.

‘Demystifying Grafted Tomatoes’ is just one of many webinars produced by OSU Extension to supplement your OSU Master Gardener continuing education.  If you missed any previous webinars from 2017 or 2018 – please take the time to view the recordings.

Each webinar viewed counts as 1-hour continuing education credit for Perennial Master Gardeners.

2018 Webinar Series

2017 Webinar Series–4l3B4VCJPvw

2019 Master Gardener Training Begins!

Our annual OSU Master Gardener training has commenced!  We welcome over 190 eager Interns, extend sincere gratitude to our inspiring instructors, and express our utmost thanks to 3 committed teams of Perennial MG volunteer coordinators!

Our supporting associations the Clackamas, Multnomah and Washington County Chapters of the Oregon Master Gardener Association are serving up a grand, trifecta with 3 fundraising plant sales.  Be sure to mark your calendars for 3 weekends filled with plants for every gardeners heart!

Washington County Master Gardener’s

Gardenfest Plant Sale

Clackamas County Master Gardener’s

Spring Garden Fair

Multnomah County Master Gardener’s

Incredible Edibles Plant Sale

Natter’s Notes

Fertilizing Garden Plants

Jean R. Natter, OSU Master Gardener

As we discussed last month, the cue to start fertilizing seedlings of seasonal flowers and vegetables is by using a commercial trick: Apply a liquid fertilizer at half, or quarter, strength as soon as the cotyledons (seedling leaves) change position from vertical to horizontal. An early fertilization such as this will give your seasonal flowers and vegetables a running start toward the abundant harvests you expect. (Fertilizing Seasonal Vegetables and Flowers; Metro MG Newsletter; February 2019:

A brief overview

Fertilizer deficiencies in landscape plants are uncommon in our region’s clay-based soils. Typically, potassium (K), phosphorus (P), and magnesium (Mg) are present in sufficient quantities for most plants.  Even so, it’s worth knowing that nitrogen is the element most often in short supply because it is water-soluble.

Nitrogen deficiency is characterized by pale and/or stunted growth; oldest leaves that turn yellow and may also dry and shrivel; along with dark green tip growth. (That’s true only if the plants received appropriate amounts of light and water for their kind.)

Growing in containers may complicate things. The soilless planting mixes used in containers, combined with a severely restricted root space, offer plenty of opportunities for plant problems. Here’s where a commercial potting mix premixed with a bit of fertilizer will come in handy for at least the first season to maintain woodies.

Eventually, though, container gardeners must periodically add fertilizer elements needed for growth, more often than in a ground bed. Even so, nitrogen will be the most common nutrient deficiency. The frequent watering required to maintain container-grown plants readily washes out nitrogen because of its high solubility.

Then, too, long-lived container plants become rootbound after a number of years in the same container. Roots have filled all the cracks and crevices in the potting mix such that nothing gets through, not roots nor water, or even fertilizer. Roots aren’t able to function. Sometimes it’s too late to re-pot.

Samples of effective fertilizer programs

Seasonal flowers or vegetables in pots: Mix a slow-release fertilizer into the potting mix, then sidedress about 4 weeks later. If needed during the season, use a dissolve-in-water product to perk up the annuals. Don’t bother adding a high phosphorus fertilizer in the hopes it will encourage flowering. Seasonal plants must absorb the required phosphorus very early in their brief lifetime.

Seasonal flowers or vegetables in the garden: Rake a starter dose of granular fertilizer into the conditioned soil. Immediately after setting the transplants, settle the soil around their roots with a diluted fertilizer solution. Sidedress about 4 weeks later. (Again, high phosphorus isn’t needed for bloom.)

Herbaceous perennials in the garden: Proceed as for seasonal flowers the first year. If needed, sidedress in each successive year. (With ornamental grasses, consider skipping the starter fertilizer because the plants may grow too soft and flop; also consider minimizing, or skipping, any sidedressings.) With experience, you’ll learn how to “read” your plants.

Lawns: Choose from fertilizing programs for high-, moderate-, or low-input lawns. Complete details for planting and maintaining lawns are in “Practical lawn care for western Oregon”

Shrubs and trees in the landscape:

Contrary to popular opinion, established landscape shrubs and trees seldom need fertilizer, especially if they are supplied with an organic mulch such as bark dust or wood chips out to the dripline. Bark chips, 3 to 4 inches deep, are recommended for trees or use bark dust, but to only 2 inches deep. That sort of program is similar to following nature’s lead: Maintain an organic mulch around the base, both to slowly fertilize the trees and shrubs as the mulch degrades in place, also to conserve soil moisture and to minimize fluctuations of soil temperatures. (Yes, you’ll still have to weed now and then.) The main undesirable effect of fertilizing long-lived landscape trees and shrubs is that doing so increases the frequency for pruning.

If you think that you absolutely must fertilize woodies, apply granular nitrogen after the new leaves have fully expanded. Then, they’re able to put fertilizer to good use while they photosynthesize. (Broadcast it underneath the canopy, out to the dripline.) Fertilizing at other times of year may produce new growth but the tree must use its own reserves, not the fertilizer, to do so.

This, by the way, brings an important caution to mind: Never fertilize a stressed tree because it needs all its reserves to survive the stress.

Blueberries would be notable exceptions to the take-it-easy guidelines for landscape woodies, simply because you want them to fruit well. See Growing Blueberries in Your Own Garden

Roses are another exception to laid-back fertilizing because, this time, the desired yield is abundant flowers for outdoor display and probably also as indoor cut flowers. Obtain a “rose fertilizer” from a large garden center or use one of the formulations available from the Portland Rose Society, then apply according to directions. ( Don’t bother with homemade concoctions.


Soils and Fertilizers (chapter 2 in Sustainable Gardening, the MG handbook)

Fertilizing Shade and Ornamental Trees

The PDF Version:
Fertilizing Garden Plants