Research Update: Studying Willamette Valley’s Native Plants

Getting ready to install plants at our field site.

The post below comes from Aaron Anderson, a M.S. student in the OSU Department of Horticulture, and a member of the Garden Ecology Lab.

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This past summer, we conducted the first field season of a study screening native plants for their attractiveness to pollinators and natural enemies. We selected 23 native Willamette Valley wildflower species based on drought tolerance, as well as four exotic garden species known to be attractive to bees: Nepeta cataria ‘Catnip’; Salvia elegans ‘Pineapple Sage’; Origanum vulgare ‘Italian’; Lavandula intermedia ‘Grosso’.

Table 1.  Native plants selected for this study.

Plant Species Common Name Life History Bloom Color
Clarkia amoena Farewell-to-spring Annual Pink
Collinsia grandiflora Giant blue eyed Mary Annual Blue
Gilia capitata Globe gilia Annual Blue
Lupinus polycarpus Miniature lupine Annual Purple/Blue
Madia elegans Common madia Annual Yellow
Nemophila menziesii Baby blue eyes Annual Blue/White
Eschscholzia californica California Poppy Annual Orange
Helianthus annuus Common sunflower Annual Yellow
Phacelia heterophylla Varied-leaf phacelia Annual White
Acmispon (Lotus) parviflorus Annual White/Pink
Achillea millefolium Yarrow Perennial White
Anaphalis margaritacea Pearly everlasting Perennial White
Asclepias speciosa Showy milkweed Perennial Pink/White
Aquilegia formosa Western red columbine Perennial Red
Aster subspicatus Douglas’ aster Perennial Purple
Camassia leichtlinii Common camas Perennial Purple/White
Eriophyllum lanatum Oregon sunshine Perennial Yellow
Fragaria vesca Wild strawberry Perennial White
Iris tenax Oregon iris Perennial Purple
Sedum oregonense Cream Stonecrop Perennial Yellow
Sidalcea virgata Rose Checkermallow Perennial Pink
Sisyrinchium idahoense Blue-eyed grass Perennial Blue/Purple
Solidago canadensis Goldenrod Perennial Yellow

We planted them in meter squared plots at OSU’s North Willamette Research Center. Between April and October, we monitored floral visitation, sampled visiting insects using an “insect vacuum”, and tracked floral bloom.

With one season in the books, we have some purely anecdotal impressions of which wildflower species are the most attractive to bees. Goldenrod (Solidago canadensis) and Douglas aster (Symphyotrichum subspicatum) were both highly attractive to a wide diversity of native bees, as well as to a variety of beetles, bugs, and syrphid flies. As an added bonus, both these species had long bloom durations, providing habitat and colorful displays for significant portions of the summer. Annual flowers Clarkia amoena and Gilia capitata attracted a range of native bees; Clarkia was also visited by leafcutter bees for a different purpose – cutting circular petal slices to build nest cells with.

Bumblebee on Clarkia.

Syrphid fly on Goldenrod.

Results from this year need to be analyzed, and further research is needed to account for seasonal variability and to gather more data on floral visitors.

Additionally, w e will ask the public to rate the attractiveness of each of our study flower species in an effort to determine the best candidates for garden use. After a few more field seasons (and sorting lots of frozen insect samples!), the result of this study will be a pollinator planting list for home gardeners, as well as a pollinator and natural enemy friendly plant list for agricultural areas. These will help inform deliberate plantings that increase the habitat value of planted areas.

Plant of the Week: Farewell-to-Spring

A leaf-cutter bee found on farewell-to-spring at the North Willamette Research and Extension Center.

This entry is from Lucas Costner, an undergraduate horticulture major at Oregon State University.  It highlights one of the plants that Aaron Anderson is using in his research.

Clarkia amoena or, as it is commonly known, farewell-to-spring, is a personal favorite of mine. An annual plant found throughout coastal areas ranging from British Columbia to California, the showy farewell-to-spring offers color, structure, and a lengthy bloom time for a variety of uses in the garden (1, 2). It is hardy from USDA zones 2 through 11, and prefers well-drained soil of average fertility (2). The type variety features upright stems with lanceolate leaves and cup-shaped pink and purple flowers, sometimes with reddish markings on the inside of the petals (1). There are cultivated varieties widely available for purchase as well, often with more profuse and different colored blooms (1). While farewell-to-spring is an annual plant, it will readily self-seed in areas meeting its rather undemanding growing conditions (1). You can, therefore, expect to see it year after year once established. Seeds can be sown directly on the surface of the soil in either fall or spring (2).

At the North Willamette Research and Extension Center, where we are conducting our native plants study, we have observed a number of insect pollinators visiting farewelll-to-spring, as well as a hummingbird, which managed to both startle and distract me while performing pollinator observations. Another honorable mention is due to the leaf-cutter bee, which Aaron and I witnessed time and again munching off pieces of Clarkia petal and carrying them to some unknown location. The USDA lists European honey bees, native bumbles and mason bees, as well as butterflies amongst the main insect pollinator visitors (2). These species, in addition to those anecdotally observed in the field, suggest that farewell-to-spring could be an excellent native addition to pollinator gardens, providing general forage to a wide variety of species.

 

Sources:

1. “Clarkia amonea.” Plant Finder, Missouri Botanical Garden, www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=283040&isprofile=0&.

2. Young-Mathews, A. 2012. Plant fact sheet for farewell to spring (Clarkia amoena). USDA-Natural Resources Conservation Service, Corvallis Plant Materials Center, Corvallis, OR.

Plant of the Week: Western Pearly Everlasting

One of the western pearly everlasting specimens from our Native Plant study.

Now that our lab group is working on native plants and native bees, I thought it would be fun to do a ‘Plant of the Week’ and ‘Bee of the Week’ series.  This entry is from Lucas Costner, an undergraduate horticulture major at Oregon State University.  It highlights one of the plants that Aaron Anderson is using in his research.

Out of all the plants we have looked at this field season, the western pearly everlasting (Anaphalis margaritacea) has been one of the most interesting. Initially not sure what to expect, the overall longevity, profuseness of bloom, and general hardiness in response to the growing conditions at our site and the wrath of some weeders/mowers have all been surprising. Suffice it to say the name pearly everlasting is well-deserved. These plants, bursting with small white and yellow disk-shaped flowers, can grow up to 3 feet in height and up to 2 feet in width (2).

The western pearly everlasting is a perennial (2) native to and found throughout most of the continental United States and Canada, excluding the southeastern states and notably North Dakota (1). It is the only naturally occurring species of the genus Anaphalis in North America (1), and is hardy through USDA zones 3 to 8 (2). In terms of care, pearly everlasting is very self-sufficient — just add sun! It grows well in areas with full sun to part shade, is drought tolerant, and requires little in the way of fertilizer or other soil amendments (2). Given the opportunity, western pearly everlasting has been known to spread aggressively in the soil via runners (2).

These plants are also interesting because they exhibit dioecy (3), meaning that the flowers are either male or female. This is rare amongst other members of the Asteraceae family, but it is a great evolutionary strategy to limit self-pollination. Purportedly, the plant plays host for caterpillars of the American Lady butterfly (Vanessa virginiensis) (4). Outside of this, however, the wildlife benefits are largely unknown.

After witnessing the vivacity of the western pearly everlasting myself, I think it would be of interest to anyone looking to fill a particularly dry and difficult area of the garden with a pleasant, native wildflower. While some of the other plants I have written about here (Solidago canadensis and Asclepias speciosa) are known to be spready, I cannot overemphasize how vigorously this plant has grown in the field. Every week I find myself being surprised by some new plantlet popping its head out the hard dry soil or a new set of inflorescences about to go into full bloom.

References:

  1. Fertig, Walter . “Pearly Everlasting (Anaphalis margaritacea).” Forest Service, USDA, www.fs.fed.us/wildflowers/plant-of-the-week/anaphalis_margaritacea.shtml. Accessed 5 Sept. 2017.
  2. “Anaphalis margaritacea.” Plant Finder, Missouri Botanical Garden , www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=j330. Accessed 5 Sept. 2017.
  3. “Pearly Everlasting.” In Defense of Plants, 22 Sept. 2015, www.indefenseofplants.com/blog/2015/9/22/pearly-everlasting. Accessed 5 Sept. 2017.
  4. “American Lady .” Butterflies and Moths of North America, 30 May 2015, www.butterfliesandmoths.org/species/vanessa-virginiensis. Accessed 5 Sept. 2017.

Plant of the Week: Canada Goldenrod

A bee visits one of the Solidago canadensis plots in our Native Plant study.

Now that our lab group is working on native plants and native bees, I thought it would be fun to do a ‘Plant of the Week’ and ‘Bee of the Week’ series.  This entry is from Lucas Costner, an undergraduate horticulture major at Oregon State University.  It highlights one of the plants that Aaron Anderson is using in his research.

Canada goldenrod (Solidago canadensis) is a perennial forb in the Aster family (Asteraceae), native and extant throughout most of North America, including of course the Pacific Northwest (1, 3). Perhaps due to its extensive range, Canada goldenrod exhibits a great deal regional variation with five varieties of the plant in current recognition (3). In the Northwest, Canada goldenrod typically flowers in late summer (2), bursting with small, star-shaped yellow flowers that are attractive to a variety of insects.

Aaron likes to refer to the species as an insect “truck-stop”, emphasizing both the spectrum of visiting insects as well as the pollen and nectar resources made available to pollinators. In the field, we have observed visits from yellow-faced bumblebees, honey bees, long-horned bees, and syrphid flies (just to name a few). The USDA notes that the plant is visited by at least two beneficial wasp species, as well as many species of native, specialist bees (1).

Generally speaking, Canada goldenrod is a low-maintenance species. Given sufficient sunlight, the plants require little in terms of additional water or fertilizer. It easily forms large colonies, spreading aggressively by both rhizomes and seeds (3). That being said, it might not make the best choice for all gardeners, considering its ability to spread and persist in a site. If space and management are not of concern, however, Canada goldenrod can be used to create impressive drifts of yellow flowers and pairs well with other prairie plants. The brightly colored spikes can also be used to make an interesting cut-flower.

References:

  1. Pavek, P.L.S. 2011. Plant guide for Canada goldenrod (Solidago canadensis). USDA-Natural Resources Conservation Service. Pullman, W A.
  2. “Solidago canadensis: Canada Goldenrod.” Washington Native Plant Society, 8 Nov. 2007, www.wnps.org/landscaping/herbarium/pages/solidago-canadensis.html. Accessed 16 Aug. 2017.
  3. Coladonato, Milo. 1993. Solidago canadensis. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/plants/forb/solcan/all.html [2017, August 16].

#OverlyHonestMethods

#OverlyHonestMethods is a hashtag that is trending on Twitter.  With this hashtag (which is simply an easy way to sort and find posts), scientists share the honest, ugly truth behind research.  Some examples:

  • “Data was not recorded on Sundays because I didn’t feel like coming in, and not recorded on this day because spiders”
  • “Got a random number by asking my mom for a 3 digit number b/c I was too lazy to use an actual random number generator”
  • “Only read the abstract of the paper cited because I don’t have any money to pay for the full paper.”

This past week, I felt like I was swimming in my own #OverlyHonestMethods research sorrow.

For starters, my particular project in the Garden Ecology Lab is to document pollinator biodiversity within 24 Portland-area gardens.  I LOVE this project.  It’s the project I’ve wanted to do since I arrived at OSU, in 2007.  But, there are two minor issues with this project.

Distribution of 24 gardens, being sampled for insect pollinators, 2017-2019.

Blue, yellow, and white pan traps ~ placed into home gardens to passively sample insect pollinators.

One of our beautiful, Portland-area garden study sites.

First, it takes me 6.5 hours to drive to all sites, in one day.  This is without doing any of the actual research.  I had originally planned to sample all gardens June 21-23 ~ but this plan was quickly scrapped when I realized that there would be no way that we could physically drive to all gardens, set traps, sample for 10 minutes, and then return to pick up all traps the next day.

Working dawn to dusk, we were only able to sample 13 of our 24 gardens, June 21-22.  So, we pushed our second set of garden samples (the remaining 11 gardens) to June 29-30.  Not ideal ~ but this is why we are replicating our study across three years, and will be sampling gardens once a month, for 3-5 months, within each year.

The other major issue with this study, this month, is that I am chairing the International Master Gardener Conference.

In less than one week, I’ll be welcoming nearly 1,300 Master Gardeners to Portland ~ for a conference that begins on July 9th (pre-tours), and ends on July 17th (post-tours).  That means that my crew and I have been stuffing 1,300 envelopes and bags.  We’ve printed and are putting 3,900 meal tickets into 1,300 badges.  I can’t over-emphasize how much work this conference has been (and continues to be!).  On the one hand, sampling pollinators just before this conference is the LAST thing I needed to do.  On the other hand . . . after spending too many late nights in a hot room, filled with boxes and boxes of conference envelopes, sampling garden pollinators is exactly what I needed.

Of course, when it rains, it pours.  Last week, we also had issues with our Native Plant study.  On Tuesday, I get a call from Aaron, who tells me that:  (1) someone trespassed onto our plots, and sprayed herbicide, and (2) someone pulled our plants up, by the roots, in one of our study blocks (replicates).

Native plant plot. This poor plant was ripped out of the ground, and/or had herbicide applied in the vicinity.

Native plant plot. This one was spared the wrath of wreckless weeders and herbicide applicators.

It’s a long (and enraging) story.  But, long story short ~ we lost all of the plants in our fifth study block.  We only have five blocks / replicates in this study (with 24 plant species ~ it is both expensive and expansive to include more blocks).  So, in one sad, sad day ~ we lost 20% of our replication, which will have negative impacts on our statistical power.

How will we cope?  We’ll regroup and replant.  We were already planning on repeating this study in 2018. Now, it seems like we’ll have to repeat in 2018 AND 2019 ~ which is a bummer . . . because this will extend Aaron’s time in grad school, will cost me 50% more to get him through grad school, and generally makes a sad, sad day for all.

But, the silver linings are: I love working with Aaron, and don’t mind supporting him for an extra year, and Aaron had already mentioned that he might want to stay on for a Ph.D., which would necessarily lengthen and/or expand the scope of his study.

C’est la research.  Perhaps in 2-3 years, we’ll all be able to have a good chuckle about this challenging month.

 

Plant of the Week: Showy Milkweed

A monarch butterfly on showy milkweed. Image Courtesy of US Fish and Wildlife. Image Source: https://www.fws.gov/pacific/images/feature/2017/highlights/Milkweed.jpg

Now that our lab group is working on native plants and native bees, I thought it would be fun to do a ‘Plant of the Week’ and ‘Bee of the Week’ series.  This second entry is from Lucas Costner, an undergraduate environmental science major at Oregon State University.  It highlights one of the plants that Aaron Anderson is using in his research.

The showy milkweed (Asclepias speciosa) is a perennial forb, native to the western United States and Canada(3).  It is hardy through USDA zones 3a to 9b (1). While the showy milkweed is listed as threatened in Iowa, it can become fairly weedy once introduced to gardens if left unmanaged, due to rhizomatous growth

(3). The plants do best in full-sun, and are an excellent choice for gardeners looking for a low-maintenance, native plant that is very attractive to pollinators (3). In particular, the showy milkweed is known for its attractiveness to the monarch butterfly (Danaus plexippus), which utilizes the plant for habitat, as well as a larval host plant and adult nectar source (1,2,3). The monarch butterfly is not alone in its use of the showy milkweed.  Eleven other species of Lepidoptera are known to reproduce on milkweeds (2), and the flowers are frequented by many species of bees and hummingbirds (1). The flowers are an appealing addition to the garden from an aesthetic perspective as well, featuring large, dense umbels of pink star-shaped flowers from May through September (3). The stems can reach heights of up to five feet and

have oppositely spaced, elongate leaves that are gray-green in color and covered in small hairs (3). At the end of the season, the flowers form interestingly shaped fruit pods packed with seeds whose silky white hairs are specially adapted for wind dispersal.

1. ”Showy Milkweed for Western Monarchs.” Monarch Butterfly Garden. N.p., n.d. Web. 26 June 2017. <http://monarchbutterflygarden.net/milkweed-plant-seed-resources/asclepias-speciosa/>.

2. Tallamy, Douglas W. Bringing Nature Home: How You Can Sustain Wildlife with Native Plants. Portland: Timber Press, 2009. Print.

3. Young-Mathews, Annie, and Eric Eldregde. Plant fact sheet for showy milkweed (Asclepias speciosa). Corvallis: USDA- Natural Resources Conservation Service, Aug. 2012. PDF.

 

Plant of the Week: Broadleaf Stonecrop

Now that our lab group is working on native plants and native bees, I thought it would be fun to do a ‘Plant of the Week’ and ‘Bee of the Week’ series.  This first entry is from Lucas Costner, an undergraduate environmental science major at Oregon State University.  It highlights one of the plants that Aaron Anderson is using in his research.

Sedum spathulifolium (Broadleaf stonecrop)

  • Wildlife benefits: larval host plant for elfin butterfly larvae; adult butterflies will nectar on blossoms

Broadleaf Stonecrop. Photo by Greg Dahlman. https://www.flickr.com/photos/enkindler/5892806011

The broadleaf stonecrop (Sedum spathulifolium spp. spathulifolium) is a perennial that is native to California, Oregon, Washington, and British Columbia (1).  It is hardy throughout USDA zones 4 to 10 (2) and is therefore well-suited to most Oregon gardens. The broadleaf stonecrop performs best in full-sun to part-shade (2), and does well in relatively dry, nutrient poor soils (3). Between the months of May through August, expect yellow star-shaped flowers clustered on stems averaging six inches in height (3). These flowers are purported to be attractive to insect pollinators, in particular butterflies (3). The blue-green leaves of the plant are succulent, develop in a rosette, and often appear waxy or powdery (4). Due its resilient nature and attractive appearance, the broadleaf stonecrop is a popular choice for Oregon gardeners looking to incorporate succulents and native plants into their landscapes. 

Sources:

1 “Plant Profile for Sedum spathulifolium spathulifolium (broadleaf stonecrop).” Natural Resources Conservation Services. USDA, n.d. Web. 25 May 2017.

2 “Sedum spathulifolium.” Las Pilitas Nursery . N.p., n.d. Web. 25 May 2017. <http://www.laspilitas.com/nature-of-california/plants/629–sedum-spathulifolium>.

3 “Sedum spathulifolium.” Lady Bird Johnson Wildflower Center. The University of Texas at Austin, n.d. Web. 25 May 2017. <http://www.wildflower.org/plants/result.php?id_plant=SESP>.

4 “Sedum spathulifolium var. spathulifolium.” Flora of North America . N.p., n.d. Web. 25 May 2017. <http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=250092154>