Author Archives: Jen Hayes

Top 10 Oregon Native Plants for Pollinators: Week 2

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The Garden Ecology Lab’s Pollinator Plant PR Campaign Presents….. Oregon Sunshine! ☀️

The Garden Ecology Lab is releasing a series of plant profiles of the top 10 Oregon native plants for pollinators, based on Aaron Anderson’s 2017-2019 field trials of 23 Oregon native plants. We will feature one plant per week for 10 weeks, this is week 2! Profiles will include photos, planting information, and will highlight common pollinators of each plant.

Plant Facts

  • Scientific Name: Eriophyllum lanatum
  • Other names: Common woolly sunflower
  • Life Cycle: Perennial
  • Foliage: grey, woolly lobed leaves
  • Growth Habit: Upright, spreading, “shrubby”; typically 12-14″ in height, may need to be cut back if it becomes too leggy to maintain upright flowers.
  • Bloom Duration: June – September
  • Hardiness Zone: 5-10; can tolerate cold up to -15 F
  • Special Traits: Drought tolerant
  • When to plant: Starts can be planted in the spring or fall, seeds should be sown in the fall.

Pollinator Facts

  • Oregon Sunshine provides both nectar and pollen to its insect visitors.
  • Oregon Sunshine was found to be associated with one species of bee in Aaron’s research: Panurginus atriceps, the black-tipped miner bee.
  • Oregon sunshine is a host plant to 7 moths: the Gernaium Plume Moth, Orange Tortrix Moth, the Lupine Ghost Moth, and three moths without common names: Telethusia ovalis, Phalonidia latipunctata, and Phtheochroa aegrana.
  • Butterflies including orange sulfurs, red admirals, commas, and skippers are also often attracted to Oregon Sunshine.

Oregon Sunshine‘s Native Range in Oregon

Oregon Sunshine commonly grows on both sides of the Cascades as well as through Southern Washington and California, and has at least 6 different varieties present across the state of Oregon (slide 2).

Maps and legend acquired from the Oregon Flora Project, with Imagery Sourced from Google. Copyright 2021© TerraMetrics

Oregon Sunshine as a pollinator plant

Oregon Sunshine is a widespread perennial in the sunflower family (Asteraceae). It provides resources to a great diversity of pollinators, including bees, butterflies, moths, and caterpillars. This native sunflower is a great late summer nectar plant with wide yellow flowers (sometimes up to 2″ across) that allow pollinators easy access to their nectaries! 

Infographics developed by LeAnn Locher, Aaron Anderson, and Gail Langellotto.
Abundance and Diversity Calculations. Bee abundance was calculated using estimated marginal means of bee visitation to each of our study plants from 5-minute observations conducted from Aaron's 2017-2019 field seasons. Estimated marginal means (EM Means) were assigned to categorical values and averaged across years to yield the following categories: 0% = Very Low =EM mean below 0.49; 25% = Low = EM mean of 0.50 to 0.99; 50% = Moderate = EM mean of 1 to 1.49; 75% = High = EM mean of 1.50 to 1.99; and 100% = Very high = EM mean above 2.0.

Bee diversity was based on the total sum of species collected on each of our study plants from 2017 to 2019. A Chao 2 Estimator was used to estimate total expected species richness for each plant; Chao 2 estimates were then used to create categorical values, as follows: 0%  = Very Low = 9.99 or lower; 25% = Low = 10 to 14.99; 50% = Moderate = 15 to 19.99; 75% = High = 20 to 24.99; 100% = Very high = 25 or higher.

Did you know?

The white-grey trichomes (the little hairs on the stems and leaves) add a lovely color to gardens and also act as an important adaptation for this drought-tolerant plant. The trichomes help Oregon Sunshine conserve water by both reflecting heat and reducing the amount of air that moves across a leaf’s surface. Though this trait helps Oregon Sunshine endure intense, dry landscapes, it can also explain why it might not do well in the gardens of those with a tendency to “kill with kindness”… this plant does not want a lot of water! It should be watered no more than once a month once established, so over-waterers beware!

Photos from the field

  • Photo by Signe Danler
  • Photo by Signe Danler
  • Photo by Signe Danler

Tune in next week for the next edition of our Pollinator Plant PR Campaign.

2021 Field Update: Natives & Nativars

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Our second field season studying pollinator visitation to Oregon native plants and native cultivars spanned from April to late September of 2021, although if Douglas Aster had any say in the matter, we would likely still be sampling. The densely blooming Symphyotrichum subspicatum continued to produce a smattering of new flowers through November of last year, and we predict it will do the same this year, too!

Our field crew this summer included Tyler, Svea, Mallory and I. Together, we sampled on 33 different dates across the growing season, allowing us to collect around 2000 physical pollinator specimens, and observe 6,225 unique interactions between pollinators and our study plants! This season we conducted floral trait measurements (including the dimensions of flowers), took multispectral photos, and additionally collected pollen from a subset of our study plants.

From left to right: Mallory vacuum-sampling off of Douglas Aster 'Sauvie Snow', Tyler shaking a farewell-to-spring flower to get pollen off of it, and Svea photographing Baby Blue Eyes 'Penny Black'.

This year, we introduced a third cultivar for California poppy (Eschscholzia californica ‘Purple Gleam’), yarrow (Achillea millefolium ‘Moonshine’), and farewell-to-spring (Clarkia amoena ‘Scarlet’). The new cultivars were established in the spring, which resulted in a late bloom for the annuals, so we expect to see them blooming during their typical period in 2022. The Achillea ‘Moonshine’ replaced Achillea ‘Salmon Beauty’ in being the most abundant yarrow cultivar; it began blooming almost immediately as it was planted into our field site and is still continuing to push out blooms through October alongside the Douglas Asters. 

The plant groups in our study: the larger circles with orange text are the native plants, and the smaller circles and turquoise text are the cultivars. The top row contain the perennials yarrow, western red columbine, great camas, and Douglas aster. The bottom row shows the three annuals farewell-to-spring, California poppy, and baby blue eyes.

In addition to watching new plants bloom in the study garden, we had the opportunity to observe many incredible pollinators in the field this summer. We saw a hummingbird visit the Western Red Columbine, we tried to capture videos of leaf-cutter bees snipping little petal pieces off of farewell-to-spring, and at a neighboring plot we observed a male wool-carder bee section off an entire patch of Salvia for a female bee.

On the left: Farewell-to-spring 'Scarlet' with crescents cut out of the petals by leafcutter bees. Top right: A female wool-carder bee (Anthidium manicatum) collecting trichomes from Yarrow 'Calistoga'. Middle right: A leafcutter bee with a piece of petal from Farewell-to-spring 'Dwarf White'. Bottom right: A leaf cutter bee removing a piece of petal from Farewell-to-spring 'Aurora'.

We were also able to take a couple educational field trips this field season in order to learn about pollinator studies ongoing outside of Oak Creek. In June, we went up to the North Willamette Research and Extension Center in Aurora, OR to listen to three talks about pollinators at the Blueberry Field Day. We learned how to score the productivity of honeybee hives, how to properly don a the top of a bee suit, about blueberry’s best pollinators, and blueberry research projects at the University of Washington.

In August, we made a trip to Bend for a different kind of study… an artistic one! We travelled to the High Desert Museum in order to visit Jasna Guy and Lincoln Best’s exhibit “In Time’s Hum…”. Jasna is a brilliant artist inspired by pollinators, which translates into the subject of her pieces as well as her artistic media. Many of her pieces are made using encaustic (a method of painting using wax, bee’s wax in her case!), dipped directly into bee’s wax, or involve pollinators in some other format, including her color study of pollen, which attempts to replicate the colors of fresh pollen as well as the colors after bees have mixed them with nectar. In the center of exhibit were two cases filled with bees collected and identified by Linc, surrounding some of the dried plant specimens they forage on.

These field trips were a wonderful way to see what other pollinator work is happening in our broader community and to inspire future studies. It was especially exciting to see how Jasna and Linc combined art and science with their exhibit, which is something many of us in the Garden Ecology Lab are interested in. 

1. Mallory, Svea, and Jen at the blueberry Field Day. 2. Svea, Jen, Mallory, and Tyler at the High Desert Museum. 3. A panorama of the "... In Time's Hum ... " exhibit. 4-5. Art on the outside of the exhibit. 6. A snapshot of two pollen samples from Jasna Guy's pollen color study.

While we cannot make conclusions until we complete our final field season, we are excited to report some of the variation in visitation between native plants and native cultivars that we have observed in our first two field seasons. In the first field season, our observations of native bees foraging on the study plants revealed three plant groups to have variable amounts of visitation. Yarrow, farewell-to-spring, and California poppy all had at least one cultivar that received substantially less native bee visits than the native type. In our second year, all three of farewell-to-spring’s cultivars received less visitation than the native Clarkia amoena. Poppy had only one cultivar with less native bee activity than the native (Purple Gleam), and in the case of Douglas Aster, both of the cultivars actually had more visitation by native bees than the native. 

Figure 1: Average Abundance of Foraging Native Bees during 5-Min Observations in 2021. Individual plants are color-coded by genus. The naming scheme combines the first three letters of the genus and specific epithet; cultivars are denoted by an underscore and a 1-2 letter code to identify them. For example, AQUFOR is the native Aquilegia formosa, and AQUFOR_XT is Aquilegia  x ‘XeraTones’.

Spring with the Mason Bees

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Written by Mallory Mead

My name is Mallory Mead, and I am new to the Garden Ecology Lab! I am an undergrad studying Horticulture and minoring in Entomology, and I started a few weeks ago as an assistant to Jen Hayes on her study of pollinator attraction to native plants and nativars.

I enrolled in Oregon State’s URSA Engage program, which gives undergrads a taste of research experience in the Winter and Spring of their first year, and joined a project studying how mason bees might be impacted by climate change with Dr. Jim Rivers of the department of Forest Ecosystems and Society. The study seeks to examine the effects of warming temperatures on mason bee behavior and the development of brood.

The Western US’s native species of mason bee, the Blue Orchard Bee (BOB) is known to be an excellent orchard pollinator. On many orchard crops they are more efficient at pollination than honey bees on a per individual basis, and so the commercial management of BOBs is being explored as honey bee colonies suffer management challenges and colony losses in recent years.

A mason bee nest within a reed. “DSC_0082” by tpjunier is licensed under CC BY 2.0.

Mason bees have a short lifespan of 4 to 6 weeks. Emerging in the early spring, males die shortly after mating, while females build nests in holes in wood or reeds. They forage for pollen and nectar to form provision masses in which they lay their eggs. They also collect mud to form partitions between each provision mass and to cap the nest once it is full. Their offspring will feed on the provisions and metamorphose into cocooned adults to overwinter in their cells and emerge the following spring.

To ensure the bees had ample nutrient resources, the project was conducted next to the organic cherry orchard at OSU’s Lewis Brown Farm. Before the cherries bloomed, 6 nest structures were designed and constructed by Jim, Ron Spendal (a mason bee house conisuerrier) and Aaron Moore of Revolution Robotics.

Nest structures, solar panels, and camcorders at Lewis Brown Farm.

Each structure has 3 shelves with 16 nest holes each, lined with paper straws so that the nests can be easily removed and examined. The structures are solar powered, and each shelf is heated to a different increment above the ambient temperature i.e. + 0°C , + 2°C, + 4°C, + 6°C, + 8°C, + 10 °C, and + 12°C. These differentials represent many potential warming outcomes of climate change.

Nest Structure Number 2 with labelled component parts. A. The Electronics control box. B. Cocoon-release box. C. Shelves sandwiched by heating pads, and lined with paper nesting straws

Our Hypotheses

  • We predicted that female mason bees will select the warmer nests first, and that females will leave nests earlier in the morning to begin foraging because they will reach the critical internal temperature necessary for flight sooner.
  • If heated bees have a greater window of foraging time, then we predict they’ll be able to construct nests at a faster rate in the warmer nests.
  • With greater nest construction will come a greater production of offspring from the bees in the warmed nests.

But…

  • In terms of offspring quality, we predict that offspring of heated nests will emerge as weak individuals and mortality will be the highest for the heated brood.

…and we are pretty confident about this last prediction.

Insects are poikilothermic meaning their internal temperatures are determined by the environment. Past studies by researchers Bosch and Kemp have reported that mason bees who are overwintered at warm temperatures will “use up their metabolic reserves and are likely to die during the winter”. And a more recent study by researchers at the University of Arizona found that mason bees subjected to heating resulted in reduced body mass, fat content and high mortality of the mason bee offspring.

Data Collection

One of the latest male mason bees to emerge, surrounded by empty cocoons in the release box.

Our mason bees started hatching from cocoons in mid-April and began to colonize the nest structures. I captured video footage of the bees as they emerged in the morning to forage. If bees from heated nest sites emerge earlier, this will support our hypotheses that they reach their critical-for-flight temperature earlier, and get a leg-up on foraging compared to their neighbors.

I also conducted “nest checks” to track the rate of nest construction along with two other research assistants.

In the fall, the nest tubes will be extracted to examine the reproductive output, and in the following spring, offspring will be assessed for rates of mortality, offspring mass, and fat content.

Obstacles

Some of the challenges along the way have included dealing with insect pests. Spiders were easygoing inhabitants of the nest straws, for they only nested in empty straws, so we’d swap them out for a clean one. The earwigs were much more pervasive, and went for the already inhabited nests. As generalist foragers, the earwigs took advantage of provision balls of nectar and pollen that had not yet been sealed off by mud. Once I read that earwigs will indeed eat the mason bee eggs that are laid into the provision masses, I knew it was crucial to remove the earwigs from all nests, but these feisty creatures proved determined to stay. We ordered some tanglefoot, a sticky substance to trap the earwigs on their way up the structure post, and meanwhile I coaxed earwigs out with tiny pieces of grass. Jabbing them repeatedly would eventually provoke them to charge at the blade of grass and fall out from the straw.

Yellowjackets were another opportunistic nester. They’d sneak into the cocoon boxes to build nests, and always gave me a start when opening the tiny boxes. I removed their nests with an extended grabber tool and would destroy them in any way I could. I feel immensely lucky not to have been stung through this process.

The most terrifying surprise during the project was a fat snake that was living in the solar panel battery box. It popped out at me hissing while I conducted a routine check. Alas, I was too spooked to take on this unexpected visitor and let it leave on its own time.

Preliminary Findings & Observations

By mid-May, a pretty clear pattern was emerging. At each structure, the control shelf’s nests (+ 0 °C) were full and capped with mud, while the hottest shelves were almost completely empty. We will analyze nest check data to confirm that these patterns are not just arising by chance, but a study that was released this past April showed another species of mason bee in Poland following the same pattern of nest site preference and selection for cooler nest sites.

The mason bees’ unexpected behavior of avoiding the heated chambers may lead to trouble during the second part of the experiment because this means our sample size for heated offspring has become so tiny, but here it is important to note that this is mason bee project is a pilot study and so the data collected this year will simply influence more specific future research.

these preliminary findings make me think that mason bees have an ingrained sense to avoid warm nests, which might show mason bees’ adaptability in the face of climate change, that is, if they can manage to continue finding cool nests. People managing mason bees find that nests facing the morning sun are the most attractive to the bees, but I wonder how long it will be before temperatures rise and mason bees start avoiding these sunny nests.

Moving Forward

By the end of May, I’d only see a few the mason bees per visit, so the season was clearly coming to an end. I wrapped up data collection and am now spending the summer extracting data from the video footage, and checking up on the bees to ensure they are safe and sound until Fall inspections.

I am wishing the best to both the wild bees in our region and those in our study, as the temperatures skyrocket this week but with this summer’s heat wave, I don’t think we need to simulate climate change; it is right here before us. Even though it is practically inevitable that temperatures will rise to dangerous heights in my generation’s lifetime, there is so much life to be saved, and there is no time to waste.

“Blue Orchard Bee, Osmia lignaria” by SeabrookeLeckie.com is licensed under CC BY-NC-ND 2.0″

A Story of Gophers & Great Camas

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According to the staff at Oak Creek and many other gardeners and farmers I’ve had the opportunity to talk to, it appears that though 2020 was a difficult year for humans, it was truly a remarkable year for gophers and other rodents.

From left to right: wild type Great Camas, Camassia leichtlinii, the native cultivar ‘Sacajawea’, and the native cultivar ‘Caerulea Blue Heaven’.

Gophers & Camas

No matter how often a gopher was trapped and removed from Oak Creek last summer, the next week there would always be a mound of freshly turned soil on the grounds, indicating a new gopher had taken its place. While they seemed to enjoy popping up in some of the Organic Gardening Club’s beds, they had an extra fondness for my own experimental garden beds. Fresh gopher-turned soil was most commonly found in any plot growing our native Camassia leichtlinii (Great Camas) and the plots surrounding them.

Bulb size comparisons for the three varieties included in our study.

We planted our 15 camas plots in the fall of 2019. Five plots were planted with the wild type camas species, Camassia leichtlinii (Great Camas). Five more were planted with the C. leichtlinii cultivar ‘Caerulea Blue Heaven’, and the final five were planted with C. leichtlinii ‘Sacajawea’. By the spring of 2020, the camas plots were relatively untouched, aside from some minor grazing by deer on a handful of plots. In April our three camas varieties began blooming in sequence (the native first, followed by ‘Blue Heaven’ and ‘Sacajawea’, respectively), and by mid June they had all gone to seed. 

Deer browsing on early spring shoots of C. leichtlinii ‘Sacajawea’.

Though the gopher troubles seemed to really begin in June, there were signs of their activity that we did not heed. In spring of 2020 I was planting a Clarkia amoena cultivar plug. Upon removing some soil to make room for the plant, I found that the soil seemed to drop off into a massive hole beneath the plot I was planting. I shook some soil loose to fill the hole, planted my Clarkia, and moved on. Later in the season, a different Clarkia plant would be found dead, and upon its removal, another tunnel would be found beneath the top layer of soil.

By August, there had been so much gopher activity in our beds that I decided we needed to conduct a damage assessment. I asked Tyler to dig around in a Camas plot that seemed particularly ravaged by the gophers, to see if he could find any of the original 40 bulbs we had planted. His searching returned no bulbs.

Bulb Thieves

I immediately went through each of the 15 camas plots and rated them with a visual assessment of the gopher activity that we would use to determine how many bulbs likely remained in the plots. The levels we decided on were “low/no damage” “Low damage”, “Moderate Damage”, “High Damage” and “Extreme Damage”. Plots with no damage were expected to have all 40 original planted bulbs. On the other end of the spectrum, plots labeled “Extreme” were expected to have no remaining bulbs.

At the end of our field season, we dug out the bulbs from each of the camas plots so we could assess the actual damage, and so we could install fencing to keep all future gophers out. During the bulb dig, we recorded the total number of bulbs found in each plot. In the table below, I have shared the visual damage rating for each plot, the estimated number of bulbs expected to be in the plots, and the actual number of bulbs we found.

Rep #Bulb TypeVisual Damage RatingEstimated Remaining BulbsActual Remaining Bulbs
1Blue HeavenLow-no402
2Blue HeavenLow-no4066
3Blue HeavenHigh1053
4Blue HeavenHigh1066
5Blue HeavenHigh105
Totals110192
1NativeExtreme00
2NativeLow408
3NativeExtreme08
4NativeExtreme030
5NativeHigh103
Totals5049
1SacajaweaHigh100
2SacajaweaHigh100
3SacajaweaModerate200
4SacajaweaLow-no400
5SacajaweaModerate200
Totals1000
Table 1: Camas Plot Estimated and Observed Damage. Damage values are estimates of how many of the original 40 bulbs are likely to remain in each plot.

While our findings from this unexpected study of bulbs were unfortunate, they tell an interesting story. An important point to note is that many of the bulbs have divided since they were planted, which is why in a few cases we found more than the original 40 planted bulbs. Regardless, there is a clear preference for the native C. leichtlinii and native cultivar ‘Sacajawea’ bulbs over the ‘Blue Heaven’ cultivar. We also noticed that any bulbs that were planted more shallow than the recommended 2-3x the height of the bulb were missed by the gophers.

Finding the Gopher Stash

After the exploratory bulb digging, we excavated each of our camas plots to around 1 foot in depth to install fences to keep the gophers from returning to our plots. While digging out the excess soil, we would often find a bulb or two that weren’t located during the initial bulb removal (these numbers are not included in Table 1, as we did not record them). In one section where the three camas types were planted in a row, we excavated a huge section of the garden, and made an amazing discovery (extra Kudos to Tyler who did the bulk of the work on this section).

On one of the walls of the hole, we found a gopher food chamber with thick white roots sticking out of the bottom of it. We removed some soil from the entrance, and discovered a chamber filled with camas bulbs. We carefully removed them and found over 60 bulbs that had been stolen from our plots. 

The 3 excavated plots, the food chamber, and the pile of 66 bulbs removed from the burrow.

Some of the bulbs were clearly the wild type great camas, identified by their characteristic long neck. The others we suspect to be ‘Sacajawea’ bulbs, as the burrow was found in what used to be a ‘Sacajawea’ plot. Any unknown bulbs were brought to my home and planted in a planter box to be identified in the next couple of months. The ‘Sacajawea’ bulbs have variegated foliage, making them easy to pick out once their shoots appear above the soil. We won’t know if the remaining mystery bulbs are ‘Blue Heaven’ or large wild type bulbs until they bloom in the spring.

Moving Forward

On the left: Jen (me) building a gopher exclosure. On the right: Tyler finishing installing a gopher exclosure.

In November of 2020 we installed our fences, refilled the gaping holes with soil, and replanted all of the camas bulbs, including some supplemental purchased bulbs of each of the three varieties. The native Camas and ‘Blue Heaven’ were successfully replanted with 40 bulbs. We were only able to order enough ‘Sacajawea’ bulbs to achieve a density of 30 bulbs per plot, though they will receive additional geophytes if any of the mystery bulbs turn out to be variegated. The mystery bulbs have yet to push their shoots through the soil, but I will include an update on their identities when I have them. 

Thank you to Tyler, Izzy, Max, and my fiancé Elliot for helping out in this laborious process. I absolutely would not have been able to safeguard the new camas plantings without your efforts and support in this process.

How do we know what flowers bees like?

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Pollinator Syndromes

Pollinator syndromes are the characteristics or traits of a flower that appeal to a particular pollinator. These traits often help pollinators locate flowers and the resources (e.g. pollen or nectar) that the flowers have to offer.

Syndromes include bloom color, the presence of nectar guides, scents, nectar, pollen, and flower shapes. We can use these traits to predict what pollinators might be attracted to certain flowers or we can use these tools to guide us to pick the right plant for the right pollinator!

Bees, for example, are most attracted to flowers that have white, yellow, blue, or ultra-violet blooms.

Blue Flax (Linum lewissii)
Male long-horned bee on a white bindweed flower
Orange bumblebee (Bombus sp.) on a sunflower

Pollinator Syndromes for Bees & Butterflies

Table adapted from the North American Pollinator Protection Campaign

TraitBeesButterflies
ColorWhite, yellow, blue, UVRed, purple
Nectar GuidesPresentPresent
OdorFresh, mild, pleasantFaint but fresh
NectarUsually presentAmple, deeply hidden
PollenLimited; often sticky or scentedLimited
Flower ShapeShallow; with landing platform, tubularNarrow tube with long spur; wide landing pad

What are nectar guides?

Nectar guides are visual cues, such as patterns or darker colors in the center of a flower, that lead pollinators to nectar or pollen. These cues are beneficial to plants and their pollinators because they can reduce flower handling time, which allows bees to visit more flowers and transfer more pollen in a shorter amount of time.

Northern Blue Flag Iris (Iris versicolor).

The petals (yellow arrow) and sepals (red arrow) both have dark purple nectar guides. The yellow portion of the sepals may also be a nectar guide!

Image courtesy of Mike LeValley and the Isabella Conservation District Environmental Education Program

While the iris’s nectar guides are visible to humans and their pollinators, this is not always the case. Some flowers have nectar guides only visible in ultra-violet light. The video below shows how different flowers look to us (visible light), and simulates what the flowers look like to butterflies (red, green blue, and UV) and to bees (green, blue, UV).

What about pinks and purples?

Red-flowering currant (Ribes sanguineum)

It’s not uncommon to see bees visiting flowers that are colors outside of their typical pollinator syndromes. In the spring in Oregon, we see bees visiting red-flowering currants, many pink and magenta rhododendrons, plum blossoms, and cherry blossoms. Lavender, catnip, and other mint-family plants too are common on pollinator planting lists, but tend to have purple flowers.

Pollinator syndromes can help us understand these anomalies. These flowers may appear differently in ultraviolet light or may have strong nectar guides that encourage bees to visit them, despite how they look to us. Alternatively, these flowers might have rich reserves of pollen and nectar that draw bee visits.

How else do we know if a flower is a good choice for bees?

Many people have developed plant lists based on personal observations, so there are many pollinator plant lists available to choose plants from. Many nurseries include pollinator attraction information with their planting guidelines too. While these are often based on anecdotal evidence, many researchers (including Aaron and I) are working to provide empirical evidence for plant selections.

To find native plants to attract bees and other pollinators, I recommend starting your plant selections by checking out your local NRCS Plant Materials program.

Many extension programs may also have regionally-appropriate plant selections! Here is the link to Oregon State’s list of native pollinator plants for home gardens in Western Oregon.

When you’re ready to buy some plants, make sure to check out this blogpost by Aaron.

Setting up a native plant and native cultivar study

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Natives Plants & Native Cultivars Recent studies report an increase in consumer demand for native plants, largely due to their benefits to bees and other pollinators. This interest has provided the nursery industry with an interesting labelling opportunity. If you walk into a large garden center, you find many plant pots labelled as “native” or “pollinator friendly”. Some of these plants include cultivated varieties of wild native plant species, or native cultivars, sometimes referred to as “nativars”. While many studies confirm the value of native plants to pollinators, we do not yet understand if native cultivars provide the same resources to their visitors.

Echinacea purpurea

Photo Source: Moxfyre – Own work, CC BY-SA 3.0,

E. purpurea ‘Maxima’

Photo Source: Ulf Eliasson – Own work, CC BY 2.5,

E. purpurea ‘Secret Passion’

Photo source: National Guarden Bureau

An Echinacea Example Above are three purple cone flower (Echinacea purpurea) plants: on the top is the wild type, in the middle is a native cultivar ‘Maxima’, and on the bottom is another native cultivar ‘Secret Passion’. In some cases, like ‘Secret Passion’s double flower, there is an obvious difference between a native cultivar and a wild type that might make it less attractive to insect visitors. Since we can’t see the disc flowers (the tiny flowers in the center of daisy family plants), we might assume that ‘Secret Passion’ may be more difficult for pollinators to visit. The floral traits displayed by ‘Maxima’ seem similar to the wild type, but it might produce less pollen or nectar, causing bees to pass over it.

Unless we observe pollinator visitation and measure floral traits and nectar, we can’t assume that native plants and native cultivars are equal in their value to pollinators.

Native Cultivar Research One study looking at the difference between native species and their cultivar counterparts has come out of the University of Vermont (my alma mater!). A citizen science effort started by the Chicago Botanic Garden is also currently ongoing. My Master’s thesis will be the first to use a sample of plants specific to the Pacific Northwest. We have selected 8 plants that are native to Oregon’s Willamette Valley and had 1-2 native cultivars available. These plants have shown a range of attractiveness to pollinators (low, medium, or high) based on Aaron’s research. We are including plants with low attractiveness because it’s possible that a native cultivar may have a characteristic that makes it more attractive, such as a larger flower or higher nectar content.

This example of a Randomized Complete Block design shows 2 garden beds containing a native species (California Poppy and Camas) and their cultivar pairs (a yellow poppy cultivar and a white Camas cultivar).

Experimental Design We have four garden beds in our study, and each bed contains at least one planting of each native species and their cultivar counterpart(s). This kind of design is called a “Randomized Complete Block” (RCB). The RCB has two main components: “blocks”, which in our case are garden beds, and “treatments”, which are our different plant species. Above I have drawn a simplified RCB using two of our plants: Camas and California poppy. The bamboo stakes outline each plot and have attached metal tags that label the plants.

We planted our seeds and bulbs in November and will plant out 4″ starts of the other plants in early Spring. Look out for my spring and summer updates to see how these plots progress from mulch and bamboo stakes to four garden beds full of flowers and buzzing insects!

Reference articles: https://www.asla.org/NewsReleaseDetails.aspx?id=53135 http://www.gardenmediagroup.com/garden-media-releases-2019-garden-trends-report