Study: Native Plants & Native Cultivars: Understanding Pollinator Preference for Native Plants and their Cultivated Counterparts in the Pacific Northwest
Thank you for your interest our survey! We are done collecting survey responses at this time. If you previously took the survey and have any questions, please direct them to Gail.Langellotto@oregonstate.edu and/or Jen.Hayes@oregonstate.edu.
This article was written for the regular column that I submit to the Hardy Plant Society of Oregon (HPSO) Quarterly Magazine. I am grateful to the team at HPSO for their editorial skills and feedback, that always improve what I write.
No Mow May is an initiative that was started in 2019 by Plantlife, a non-profit that works to restore meadow habitats in the United Kingdom. Their annual campaign called on garden owners and greenspace managers to cease mowing in the month of May, in order to move lawn-dominated yards towards a more natural approach. The movement quickly spread to other regions of the globe, as an easy and feel-good measure that almost any land manager could take to promote biodiversity and protect pollinators. In the United States, Bee City USA adopted the No Mow May campaign, which they also refer to as Mow Less Spring, as a way to conserve native pollinators.
There is some science to support the notion that less-intensely managed lawns benefits biodiversity. Our lab group even wrote about it in a blog post on No Mow May, including sharing a meta-analysis of 14 studies from North America and Europe showed that plant diversity and invertebrate diversity increased in lawns, as mowing intensity decreased [1]. However, several studies included in this review had mowing treatments that are not generally practical for most residential yards. Some studies compared lawns mowed once per week to lawns that were mowed once per year, for example. One of the few studies that compared mowing frequencies that approximate real world conditions was conducted in Springfield, Massachusetts [2]. In this study, Dr. Susannah Lermann and colleagues compared bee abundance and diversity from yards mowed every week, every two weeks, and every three weeks. Lawns mowed every three weeks had 2.5X more lawn flowers than other lawns. Interestingly, lawns mowed every two weeks had the highest bee abundance, but lowest bee species richness. The authors speculate that the higher grass height of the three-week mowed lawns covered lawn flowers, and made them less accessible to many bees. The higher lawn height also made the three-week mowed lawns less acceptable to nearby neighbors, leading the authors to suggest that a ‘two-week regime might reconcile homeowner ideas with pollinator habitat’.
That brings us back to No Mow May, and whether or not there is science to support the idea that not mowing for an entire month might benefit pollinators. In 2020 (soon after the start and spread of No Mow May) Del Toro and Ribbons published a paper that suggested that households that observed No Mow May had three times more bee species and five times higher bee abundance than spaces that were regularly mowed [3]. The results were highlighted in a New York Times story [4], and resulted in a change in the City of Appleton code that suspended an 8” lawn height restriction for the month of May, via a 6-3 split vote for and against the resolution [5]. Israel Del Toro, lead author of the study, was elected to Appleton’s Common Council, soon after leading the effort to adopt the resolution. By 2022, an additional 25 U.S. cities had followed suit [6], with their own declarations in support of No Mow May.
As the No Mow May movement grew, so did controversy surrounding the Del Toro and Ribbons study. Bee taxonomist Zach Portman noted serious issues with the bees identified in the study. Horticulture Professor Bert Cregg noted that the study was confounded, by comparing home lawns that were not mowed to park spaces that were mowed. With this experimental design, it is impossible for the authors to disentangle the effects of mowing (e.g. mowed or not mowed) from the effects of habitat type (e.g. home lawn versus park). In November of 2022, the authors retracted their study ‘after finding several potential inconsistencies in data handling and reporting’. After the retraction, the City of Appleton considered a resolution to eliminate No Mow May, claiming that the program lacks scientific backing. However, this resolution did not pass [7].
What is a science-informed gardener to do, amidst confusing and sometimes conflicting messaging related to pollinator conservation in a yard? First, note that science self-corrects, when the system works well. Retractions are part of that corrective process. Second, remember that bees can be found in lawn areas, particularly if lawns are less managed. The Lermann study demonstrated that lawns can host a surprising richness of bee species: 72, 60, and 62 bee species, in lawns mowed every week, two weeks, or three weeks, respectively. Note that to be part of this study, homeowners had to agree to not use herbicides or irrigation, during the length of the study. As a result of reduced management, lawns in this study often had bare patches that might be good nesting habitat for soil-nesting bees. Relaxing your mowing regime to every 1-2 weeks is supported by good science. Stowing your mower for an entire month is not. Finally, if you want to manage your yard for pollinators, planning and planting a pollinator garden is likely to net more species than stowing your mower. Indeed, many critics of the No Mow May movement, including native plant advocate Doug Tallamy, suggest that providing a temporary safe haven, regardless of its length of time, is counterproductive for pollinators and other wildlife it was meant to benefit. We currently have a paper in review, addressing this very topic. I look forward to sharing the highlights with readers, once it is published.
[1] Journal of Applied Ecology 57: 436-446
[2] Biological Conservation 221: 160-174
[3] PeerJ 8:e10021
[4] New York Times, March 28, 2022.
[5] Appleton Common Council resolution and vote, April 1, 2020.
[6] NBC 26 Local News, April 22, 2022.
[7] Post Crescent, April 10, 2023.
This note comes from our collaborator at the University of Oregon, Dr. Gwynne Mhuireach. Dr. Mhuireach previously worked with our lab and local gardeners to document soil microbial communities, and the extent to which the act of gardening transfers soil microbes to gardeners’ skin ~ thus affecting the skin microbiome!
At the conclusion of the skin microbiome study, many gardeners asked for more information on how gardening affects the gut microbiome. Dr. Mhuireach received USDA funding to conduct a pilot study, to address this question. Gardeners in Linn and Lane Counties are specifically invited to apply.
The deadline to apply to participate in this NEW study is August 15th.
We are seeking healthy adult gardeners to engage in a research study exploring microbiota of fresh fruits and vegetables from gardens and supermarkets, and their potential to influence the gut microbiome. To be eligible, you must be between the ages of 18–45, be fluent in English, live in Lane or Linn County, and have access to a garden that can provide enough fruits and vegetables for the diet intervention. Participants will receive $50 at the beginning of the study, $50 upon completion, and a $75 allowance to purchase supermarket fruits and vegetables.
Study activities: If you participate, you will be asked to undergo two week-long diet intervention periods during which you will eat the USDA-recommended amount of fruits and vegetables. In one period all of the produce should be sourced from your garden and in the other the same produce should be sourced from a supermarket. You will be also asked to pre-plan your meals for the intervention periods, complete a Lifestyle, Health, & Diet Questionnaire, maintain a Daily Fruit & Vegetable Log, collect samples of all the fruits and vegetables you eat, collect stool (fecal) samples, and collect a tapwater sample. The total duration of participation is 24 days, with an expected average time commitment of 20–30 minutes per day.
Potential risks: Participants will be exposed to microorganisms from garden and supermarket produce, however, this exposure occurs during normal daily life. There is also a risk that privacy or confidentiality could be breached, though precautions will be taken to avoid such breaches.
Benefits: There are no direct benefits to participating in this study.
To see if you are eligible, please use this Qualtrics link (https://oregon.qualtrics.com/jfe/form/SV_9Gn0UOtZEbzWEh8) to take a brief screening survey. More information is available at www.gffstudy.com.
On the last day of pride month, I read an article that brought me to tears: Can Entomology Emerge as a Role Model Field of Study for LGBTQ+ Inclusion and Visibility? by Michael C. Cavallaro. This year has been extremely difficult for the LGBTQ+ community, and to read about the successes and progress made in my field towards LGBTQ+ inclusion warmed my heart and gave me hope for my fellow queer bug lovers.
Before we dive in to the article, I want to share why this topic is important to me. I identify as a queer entomologist in two ways: 1) I am queer and I am an entomologist, and 2) I am interested in the ways that entomology expands and defies western understanding and expression of gender. The natural world, especially insects, teaches us that queerness is inherently natural and expressed in diverse ways.
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Cavallaro begins the article discussing “Shared Traits: Entomologists and LGBTQ+ Folks” by Rae Olsson, which mirrors many conversations I have had with my fellow queer entomologists. Us folks who grow up chasing, collecting, and admiring insects tend to be viewed as weird, odd, or even outcasts. Queer folks are often far too familiar with the feeling of being marginalized, othered, and at odds with society. But, there is an odd comfort in knowing that you are a weirdo studying something weird.
The article continues, noting the advances that ESA (The Entomological Society of America) has made in providing an inclusive environment for LGBTQ+ folks and elevating their voices. We have seen these advances in the form of inviting people to include their pronouns on the annual event badges, introducing symposia on Diversity, Equity and Inclusion (DEI) issues, and removing states with anti-LGBTQ+ laws from potential future meeting locations. He also points out recently identified insects that have been bestowed names of queer icons, which I wrote about during last year’s pollinator week post.
Cavallaro reports that 7.2% percent of ESA members have identified themselves as LGBTQ+, which reflects the U.S. national average. He notes that STEM still has many barriers to overcome as it is “rooted in a competitive and heteronormative culture” and “workspaces for queer-spectrum STEM professionals and students can be unsupportive and exclusionary.” Both STEM and entomology still have a long way to go in terms of acceptance, encouragement, and representation of queer folks.
As someone who attended a prestigious field entomology program and was called a “disney princess” on the first day, I can attest to the flippancy with which queer folks and femme-presenting folks are often treated in professional entomological spaces. It is, however, validating to witness the largest entomological organization in the U.S. taking the time to address, welcome, and better their ability to support their LGBTQ+ membership.
What is an ecolawn?
An ecological lawn, or ecolawn, is a reduced input alternative to a conventional mowed grass lawn. While numerous possibilities for an ecolawn exist, they all include multiple low-growing herbaceous plants that work well together and require less mowing, fertilizer and irrigation. In addition to reducing maintenance and resource utilization, they also provide important habitat for pollinators like bees and butterflies.
Help us find examples!
We are looking for examples of beautiful ecolawns throughout western Oregon. A few requirements:
We want to find, understand and share your (or your neighbor’s) ecolawn. Ecolawns are part of a more sustainable future for Oregon. If you have a good example, please email 2-3 photos and contact information to Dr. Phil Allen, Visiting Professor in Horticulture at Oregon State University: allephil@oregonstate.edu
Insect collections are a good hobby to have, and an even better tool for research. One might think you just go catch insects and pop them into a box, but a little more needs to happen in order to preserve them for a collection.
Depending on your collection method, washing, blow drying, pinning, and labelling all need to happen to keep our collection usable!
After doing these steps and putting them in a box, our wonderful Jen Hayes and taxonomists will identify them to species. There are so many morphs and intricacies that you may not even realize two look-alike bees may just be completely different species. My favorite thing about the process is seeing the fluffy bumblebees after blow-drying! 🐝
Anyways, here’s a short video showing how we go from catch to box!
This summer we completed our third and final field season surveying pollinator visitation to native plants and native cultivars! We will maintain our experimental garden for one additional season, to finish up some plant measurements and data collection missed in our initial three seasons. This post will serve as a 2022 field update in addition to summarizing some of our preliminary results from our field observations!
| Photo | Scientific Name | Common Name | Plant Type |
|---|---|---|---|
 | Achillea millefolium | Yarrow | Native |
 | Achillea millefolium ‘Calistoga’* | Yarrow | Cultivar |
 | Achillea millefolium ‘Salmon Beauty’ | Yarrow | Cultivar |
 | Achillea millefolium ‘Moonshine’** | Yarrow | Cultivar |
 | Aquilegia formosa | Western Red Columbine | Native |
 | Aquilegia x ‘XeraTones’ | Cultivar (hybrid) | |
 | Camassia leichtlinii | Great Camas | Native |
 | Camassia leichtlinii ‘Caerulea Blue Heaven’ | Great Camas | Cultivar |
 | Camassia leichtlinii ‘Sacajawea’ | Great Camas | Cultivar |
 | Symphyotrichum subspicatum | Douglas’ Aster | Native |
 | S. subspicatum ‘Sauvie Sky’ | Douglas’ Aster | Cultivar |
 | S. subspicatum ‘Sauvie Snow’ | Douglas’ Aster | Cultivar |
 | Clarkia amoena | Farewell-to-spring | Native |
 | Clarkia amoena ‘Aurora’ | Farewell-to-spring | Cultivar |
 | Clarkia amoena ‘Dwarf White’ | Farewell-to-spring | Cultivar |
 | Clarkia amoena ‘Scarlet’** | Farewell-to-spring | Cultivar |
 | Eschscholzia californica | California Poppy | Native |
 | E. californica ‘Mikado’ | California Poppy | Cultivar |
 | E. californica ‘White’ | California Poppy | Cultivar |
 | E. californica ‘Purple Gleam’** | California Poppy | Cultivar |
 | Nemophila menziesii | Baby Blue Eyes | Native (California) |
 | N. menziesii ‘Penny black’ | Baby Black Eyes | Cultivar |
 | N. menziesii ‘Snow White’ | Baby Blue Eyes | Cultivar |
 | Sidalcea asprella ssp. virgata*** | Rosy checkermallow | Native |
 | Sidalcea malviflora ‘Purpetta’*** | Cultivar | |
 | Sidalcea malviflora ‘Party Girl’*** | Cultivar |
We conducted 5-minute visual observations on our study plants over three seasons. During these observations, we recorded all insects that interacted with a plant. These interactions included foraging, resting, basking, mating, etc. We recorded insect IDs to morphological group levels, as many bees are hard to identify to species in the field! We were able to identify common bumble bees, honey bees, butterflies, and a few other insects to the species level, but many were identified to groups for ease (e.g. ‘green bees’, ‘black bees’, ‘leafcutter bees’).
| Year | # Sample Dates | # Collected Pollinators | # Observed Pollinators |
|---|---|---|---|
| 2020 | 28 | 2159 | 6238 |
| 2021 | 33 | 2471 | 6225 |
| 2022 | 29 | ~2000 | ~4700 |
Our initial graphs show a subtle preference for native types by native bees. Douglas’ Aster, California Poppy, Farewell to Spring, and Columbine (4/7) have higher visitation by native bees when looking at cumulative and mean counts. The difference is marginal for Douglas’ Aster, but trends for the other three plants are strong. The remaining three species (Yarrow, Baby Blue Eyes, Camas) are difficult to assess, based on these figures alone.
Across these seven species, we do see differences in visitation between natives (wild types) and native cultivars. Whether these differences are statistically significant, and whether there is a trend across all plant groups, remains to be seen!!!
I want to recognize my amazing Bee Team this year, as this field season would not have been possible without them! I am grateful for all of their hard work and their success in managing this project while I was away numerous times this season. They are thoughtful, inquisitive, and resourceful students, all of whom would make amazing lab or field technicians upon their graduation this spring! Nicole is not pictured below, but also deserves recognition for all her contributions to this project. Thank you all 🐝
What… is it already time to think about spring cleaning?! It might still be winter, but spring will be here faster than we know it. Some quick cleaning is a great way to take care of a garden that we enjoy during the year!
If you’re wondering where to start, this blog post could be a way to jumpstart your cleaning. Here’s 5 tips on things to clean in the garden.
It’s a great feeling to see all types of birds using and enjoying your bird feeder. While they’re great, bird feeders can actually pose a major threat to bird health: excrement that is on the feeder perch can pass from bird to bird, spreading Salmonella and other diseases. Even if you don’t see dead birds around your bird feeder, birds that use your feeder could still be passing disease elsewhere, after they use it. Luckily, it’s a simple fix! How to clean a bird feeder: It’s best to clean your bird feeder regularly, say in between fills. Ideally, take it inside and wash it with soap and water. Then, soak it in a bleach solution (9:1 water to bleach) for 10 minutes. Rinse again to rid the feeder of any bleach solution. Make sure to wash your hands after touching the feeder! For more information, check out this link.
Bird baths: Algae isn’t fun to look at, but did you know it’s also dangerous for birds? Luckily, there’s simple fixes to keep bird baths clean and fresh for visitors! The easiest way to help keep your bird bath clean is to wash it out regularly (sometimes even every day, especially in the summer).
There are two other mixing solution options for doing a deep clean of your bird bath: vinegar or hydrogen peroxide. Each mixture is nine parts water and one part vinegar or hydrogen peroxide. Use a scrub brush to fully clean the bath and then ensure no cleaning mixture remains. Refill with water, and you’re good to go!
For more information, check out this link.
Tools help us take great care of the garden… let’s show the same level of care to our gardening tools! Cleaning gardening tools helps to extend their lifespan and can also help prevent the spread of disease.
How to clean gardening tools: Different options exist to clean gardening tools. For those tools that have metal, you can fill a 5 gallon bucket with sand and about a quart of car motor oil. After you’re done using the tools for the day, dip them in the sand and oil mixture. This mix helps to both clean the blade and coat it in a thin layer of oil. If you want to do a deep clean, you can wipe off any tools with a damp rag and some alcohol. If there’s sap or other buildup on your tools, try using sandpaper to get rid of it. Sandpaper is also a great way to refresh the wooden handle on tools (if you want to add a layer of oil after sanding wood, try mineral oil as a finish)!
For more information, check out this link.
Happy cleaning!
The Garden Ecology Lab’s Pollinator Plant PR Campaign Presents….. Globe Gilia!
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 8! Profiles will include photos, planting information, and will highlight common pollinators of each plant.
Plant Facts
Pollinator Facts
There are three subspecies of Gilia capitata in Oregon: Bluefield Gilia (ssp. capitata), Dune Gilia (ssp. chamissonis), and Pacific Gilia (ssp. pacifica). Dune Gilia and Pacific Gilia are considered to be rare plants in California (rare, threated, or endangered, rank 1B). Distribution maps acquired from Oregon Flora with imagery from Google. Copyright 2022.
Globe Gilia as a pollinator plant
Globe Gilia may have only been associated with a single bee species in Aaron’s native plant research, but it is truly a powerhouse of an annual plant: it supports a highly diverse and abundant community of native bees! Gilia’s globe of flower heads provide pollinators with plenty of foraging spots to choose from, and the dense mass also allows easy access for both small and large pollinators, by acting as a nice landing pad. From their comfortable perch, butterflies and larger-bodied bees can dip their proboscis (tongue) into the nectar-rich blossoms. Smaller bees may need to crawl in to the individual flowers to access the nectaries.
Gilia is a great annual plant option to include in pollinator mixes and in meadows. It’s an easy to care for plant, requiring minimal water during the growing season. It grows up to three feet in height with lovely lavender – dark purple – blue flower heads, lacy foliage, and surprising blue pollen! The flowers contrast wonderfully with many other mid-summer blooms, such as poppies, Oregon sunshine, asters, and Clarkia.
Infographics developed by LeAnn Locher, Aaron Anderson, and Gail Langellotto.
Abundance 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.
Diversity Calculations. 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.
When you think about pollen, one color tends to come to mind: yellow. Perhaps you conjure up an image of a bumblebee in a field of clover, weighed down by some giant orange-toned pollen baskets as well. Many of us might stop there, and conclude that pollen must be either yellow or orange, as those are the predominant pollen colors we see in the plant world. The absolutely exciting news is that, like flower colors, pollen also comes in a rainbow of colors. Globe Gilia, for example, has pollen that comes in shades of blue!
A spotlight on pollen colors
As some of you may remember from my (Jen’s) 2021 field update, last summer, a few of us from the Garden Ecology lab had the wonderful opportunity to visit Jasna Guy and Lincoln Best’s exhibit ‘In Time’s Humm’ at the High Desert Museum in Bend. Part of this display was a pollen color study, showing Jasna’s recreations of pollen colors using pastels. We saw pollen in shades of yellows, oranges, red, pink, purple, white, and even green. Color can truly be found anywhere if you look closely enough! Perhaps it should be no surprise then, that even nectar may come in various colors, too… If you’re excited about pollen colors like we are, you might see if your local library has a copy of this book, and you might enjoy looking at pollen colors through the seasons, put together by the North Shropshire Beekeepers’ Association.
Tune in next week for the next edition of our Pollinator Plant PR Campaign.
The Garden Ecology Lab’s Pollinator Plant PR Campaign Presents….. Common Madia (AKA Tarweed)!
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 6! Profiles will include photos, planting information, and will highlight common pollinators of each plant.
Plant Facts
Pollinator Facts
Madia elegans is native to most of Western Oregon. Although it's native range does not extend east of the Cascades, it is a hardy annual that may do well in Central- and Eastern- Oregon gardens. Map acquired from Oregon Flora with imagery sourced from Google.
Common Madia as a pollinator plant
Common Madia is an ideal plant for pollinator gardens due to its long bloom duration and attractiveness to bees, caterpillars, and butterflies. Madia was found to attract both a high abundance and a high diversity of bee visitors, which further speaks to its use as a great pollinator plant! Due to it’s late-summer bloom period, Madia can act as a great source of forage for it’s various visitors when there may not be many other plants flowering in the landscape. Madia flowers, which close at dusk and reopen in the morning, may also come with a fun surprise if you catch them before the sun has finished its ascent: if you’re lucky, you may be able to find male long-horned-bees sleeping in groups within the flowers2.
Infographics developed by LeAnn Locher, Aaron Anderson, and Gail Langellotto.
Abundance 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.
Diversity Calculations. 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.
The other common name for Madia, “Tarweed”, comes from its foliage. It’s covered in stiff trichomes (hairs) and stalked glands which emit a tar-like scent. Common Madia is not the only species with this nickname, it applies to plants in the entire genus! For example, Madia glomerata, “Mountain Tarplant”, is a species of Madia native to the Northeast United States.
Common Madia‘s fruits are flattened achenes, which are valued by small mammals and birds as a food source. The achenes were also used by Indigenous groups, including the Pomo, Miwok, and Hupa and as a staple food source3. The fruits were often roasted with hot coals and then ground into flour.
Tune in next week for the next edition of our Pollinator Plant PR Campaign.