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.

As summer in the Pacific Northwest comes to a close, the sunflower (Helianthus annuus) stands out as a classic garden favorite deserving consideration. These commonly large, tall yellow flowers are a boon to wildlife, provide late summer height and interest in the garden, and have shared an interesting relationship with people wherever we have encountered them. 

While there are many individual species and varieties available on the market today, wild populations can be found across North America, and most boast popularity with insect pollinators and other wildlife, including birds (1, 3). In the field, Aaron is using the wild-type and, while you certainly don’t have to do the same, varieties marked as “pollenless” or double-petaled should be avoided when planting for wildlife (3). Sunflowers seeds are well-known for their attractiveness to birds, but the flowers also provide forage to a diverse suite of insects, including bees, wasps, butterflies, and even beetles (2, 3). Four genera of native bee species (Diadasia, Eucera, Melissodes, and Svastra) host members that are sunflower specialists, and the giant leafcutter bee (Megachile pugnata) has even been studied as a managed pollinator for agricultural production of the crop (3). 

The giant leafcutter bee (Megachile pugnata).  Photo Credit: Thomas Shahan. Oregon Department of Agriculture.

Originally domesticated in eastern North America, the sunflower is the only native seed oil plant (1). Its use among North America’s indigenous peoples is well-documented and varied, having been used for everything from food to dye to medicine (2). The sunflower was introduced to Europe in the 16th century, where it first found its place in gardens, but it wasn’t until the 1800s in Russia that our modern ideas of giant, towering sunflowers came to be (1). This is because early American colonists did not cultivate sunflowers, and the seeds were reintroduced from Russia to the United States in 1893 (2). The Russians bred sunflowers that could produce up to 1000 seeds each for oil production, since the Russian Orthodox Church had forbidden the use of other cooking oils during the Lenten season (1). Therefore, in comparison with many common varieties available, and despite 3,000 years of domestication by indigenous peoples in North America, the wild-type appears quite diminutive (2). 

No matter the variety, gardeners should be aware that sunflowers are annual flowers that will need replanting every spring (although allowing squirrels to do the planting could be a fun experiment). They prefer well-draining soil and can reach rather impressive heights depending on the exact species and type. Additionally, the stems can become woody and may require some work removing at the end of the season. 

Sources cited: 

  1. Simpson, B. B., & Connor, M. (2014). Plants in Our World: Economic Botany (4th ed.). New York, NY: McGraw-Hill Education.
  2. Stevens, M. (2006, June 7). Plant Guide: Annual Sunflower [PDF]. Davis: USDA NRCS National Plant Data Center.
  3. The Xerxes Society. (2011). Attracting Native Pollinators. North Adams, MA: Storey Publishing.

In 2017 and 2018, Aaron and Lucas took weekly counts of bees on their native plant plots. Aaron has summarized the data for 2017 (below) according to bee morpho-type. The morphotype categories are the same general categories that have been used by other researchers: bumblebee, honey bee, green bee, small bee, and big bee. These major bee categories are fairly easy to distinguish from one another in the field. Although, Aaron and I talked quite a bit about whether or not we should combine big bees and small bees into a new category: other bees. When does a small bee become a big bee? We had a general sense that a large Megachile rotundata would be a big bee, and a small Ceratina sp. would be a small bee. But, what about a smaller Megachile species? Is that big bee or a small bee? There is no clear answer.

Aaron and Lucas kept records of big bees vs small bees, as best as they could, but in the end, we might collapse all of that data into an ‘other bee’ category.Aaron recently surveyed gardeners, to ask their opinion on the aesthetics of his study plants. A quick look at the results suggests that gardeners and bees might be attracted to different flowering plants. While Gilia capitata was the most visited plant in Aaron’s study plots, it was ranked 6th most attractive (out of 27 plants) by gardeners. The story gets worse for Madia elegans (2nd with bees, 20th with gardeners), Aster subspicatus (3rd with bees, 14th with gardeners), and Solidago candensis (4th with bees, 23rd with gardeners).

Could it be that bees and gardeners are truly attracted to different types of flowering plants? Or could it be that if gardeners knew about the benefits of these Willamette Valley natives, that they might see a new kind of beauty in these plants?

 

We are so lucky that Lincoln Best has been in Oregon, supporting the work of the Oregon Bee Atlas. Linc was kind enough to take a look at Aaron’s bees, before going back to Canada. Aaron is currently taking a bit of time off, following his wedding this past weekend (Congratulations Aaron and Maura!). In everyone’s absence, I’m chomping at the bit to see what bees were identified from Aaron’s study of Willamette Valley native plants. So ~ for your reading pleasure, here is a preliminary list of bees collected from Aaron’s plant plots.

Aaron and Lucas in the native plant study site. You can see the 1m by 1 m plot in the foreground by Aaron, a second one near Lucas, and a few more in the distance.

A few things to note about this list:

  1. I give no mention of abundance of each bee species. Some specimens were caught many, many times off of a flowering plant species. Others were rare, and only caught once.
  2. This list is not all-inclusive. It’s Labor Day. I’m working. I got excited about the bees, and wanted to share. But, I am not carefully going through every small label.
  3. Some bees were only found on one or two flowering plant species ~ even though Aaron’s plots are all in the same 3 acre field (1X1m plots, with each plot separated from every other plot by 6 m).
  4. Yellow-faced bumblebees were collected off of most plants ~ so I am not listing them, below. I also did not look at the honey-bee plant associations.
  5. Linc dissected male genitalia (yes ~ that is how you need to ID some bees to species), and found FOUR Bombus calignosus (all associated with lavender)~ a vulnerable species on the IUCN Red List.
  6. We also have Bombus fervidus, another species on the IUCN Red List (Vulnerable) on lavender, Salvia, and Gilia.

I’ll leave it to Aaron to make a rigorous accounting of bee-flower associations. But for now . . . on this holiday weekend, I was too excited to not take a peek and share initial findings with all o fyou.

Nepeta (non-native comparitor)

Oregano (non-native comparitor)

Salvia (non-native comparitor)

Lavender (non-native comparitor)

Phacelia (native)

Clarkia (native)

Goldenrod (native)

California Poppy (native)

Doug Aster (native)

Oregon Iris (native)

Gilia capitata (native)

Oregon Sunshine

Madia (native)

Sidalcia (native)

Yarrow (native)

Pearly Everlasting (native)

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.

Common Yarrow (Achillea millefolium) isn’t just common — it’s nearly ubiquitous throughout the Pacific Northwest. Found in lawns, along roadsides, in fields and gardens, it’s easy to allow yarrow’s abundance to overshadow its potential in the landscape, its benefit to wildlife, and its historical value as a medicinal plant. 

A perennial native across the temperate Northern Hemisphere, yarrow has a long history of human association (1, 2). Its scientific name, Achillea, comes from the ancient Greek hero Achilles, who used the plant to help dress battle wounds (2). Similarly, in the Northwest, indigenous peoples made poultices and teas from the plant (2). 

In the landscape, it may be helpful for gardeners to consider mimicking natural distribution patterns by massing yarrow into larger groups of plants (3). Yarrow grows densely — emerging up to three feet in height and spreading from a fibrous horizontal root system (1). White, sometimes pink, ray flowers appear at the end of stems in nearly flat inflorescences (2). These plants are very drought tolerant and appear naturally in disturbed areas, meaning they will thrive in the average garden (1). 

As a member of the Asteraceae family along with goldenrod and Douglas aster, yarrow’s bountiful floral display offers excellent forage for generalist pollinator species throughout the summer months and is a common choice for butterfly gardens (1). In addition to its floral resources, the foliage is noted as a source of food and habitat to many species of butterfly and moth caterpillars (4). 

References: 

1. Hurteau, M. D. (2013, November 13). Common Yarrow [PDF]. USDA NRCS National Plant Data Center.

2. Mathews, D. (2016). Natural History of the Pacific Northwest Mountains. Portland, OR: Timber Press.

3. Rainer, T., & West, C. (2015). Planting in a Post Wild World. Portland, OR: Timber Press.

4. Robinson, G. S., P. R. Ackery, I. J. Kitching, G. W. Beccaloni & L. M. Hernández, 2010. HOSTS – A Database of the World’s Lepidopteran Hostplants. Natural History Museum, London. http://www.nhm.ac.uk/hosts. (Accessed: 29 Aug. 2018).

We are soliciting Master Gardener feedback on the attractiveness of the native wildflowers that Aaron Anderson is studying for pollinator plantings. More detail on the study can be found at:

http://blogs.oregonstate.edu/gardenecologylab/native-plants-2/

As we mention, not only are we interested in finding plants that support ecosystem services; we also want to find plants that gardeners find attractive, and that they would want.

This is where you come in. If you are willing, please let us know which ones you would like to see in your own garden, based on their looks, alone. Below is the recruitment letter, with further information about participation. Thank you for your consideration!

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Study: Screening Willamette Valley Wildflowers for attractiveness to Pollinators and Natural Enemies

Graduate Research Assistant: Aaron Anderson (andeaaro@oregonstate.edu; 503-860-9286)

Principal Investigator: Dr. Gail Langellotto (Gail.Langellotto@oregonstate.edu; 541-737-5175)

Dear Master Gardener,

You are invited to take part in a survey that will generate useful information on the ornamental value of pollinator-friendly native wildflowers.

Previous research has shown that urban greenspaces, notably gardens, can provide excellent habitat for pollinators and other invertebrates. The inclusion of pollinator-friendly plantings in gardens has the potential to improve habitat quality and connectivity in otherwise inhospitable landscapes. However, research on which Willamette Valley wildflowers are best to use for these plantings is lacking. Thus, I am conducting a research project to assess the relative attractiveness of 23 wildflower species native to the Willamette Valley (Oregon) to pollinators and natural enemies. Additionally, I would like to assess the aesthetic value of these plants to identify native flowers that are also attractive for ornamental use in home gardens.

As a Master Gardener, I am asking your help with my study, “Screening Willamette Valley Wildflowers for attractiveness to Pollinators and Natural Enemies”.  If you are aged 18 or older, and are currently a Master Gardener, or have been a Master Gardener in the past, I would appreciate it if you could take 10-15 minutes to respond to this survey:

http://bit.ly/OSUNative

Your survey responses will be recorded as a group. Thus, your response will be anonymous.  If the results of this survey are published, your identity will not be made public. The security and confidentiality of information collected from cannot be guaranteed.  Confidentiality will be kept to the extent permitted by the technology being used.  Information collected online can be intercepted, corrupted, lost, destroyed, arrive late or incomplete, or contain viruses.

Your participation in this study is voluntary and you may refuse to answer any questions(s) for any reason.  There are a limited number of Master Gardeners in Oregon, so your participation in this study is important. If you do not want to participate and do not wish to be contacted further, do not fill out the online questionnaire. There are no foreseeable risks to you as a participant in this project; nor are there any direct benefits. However, your participation is extremely valued.

If you have any questions about the survey, please contact me at 503-860-9286 or via email at andeaaro@oregonstate.edu.  If you have questions about your rights as a participant in this research project, please contact the Oregon State University Institutional Review Board (IRB) Human Protections Administrator at (541) 737-4933 or by email at IRB@oregonstate.edu.

Thank you for your help. I appreciate your consideration.

Sincerely,

Aaron Anderson

Western Columbine
California poppy
Oregon Iris

 

 

 

 

 

 

 

 

 

 

 

Over the past year, I have have given many presentations that highlighted the high bee activity at ‘site 51’; a garden that is fairly small (0.1 acre) and in a heavily developed area of East Portland. Despite its size and location, ‘site 51’ had the second highest number of bees from our 2017 collections. I suspect bee diversity will also be high at site 51.

This garden is managed by someone who is an avid Xerces Society member. He gardens specifically for pollinators, and it shows! His garden is a true testament to the idea that ‘if you plant it, they will come’.

So what plants are in this garden? Our preliminary plant list (from a brief 2017 survey) can be found below. I will add Latin names, when I have a moment. For now, I hope that the common name list might introduce you to a new plant or two that might work well in your own garden.

Several of the plants in this garden are native to the Willamette Valley, and are included in Aaron Anderson’s study of native plants. The photos in this post are from Aaron’s field research.

 

 

 

 

  • Iris
  • Nodding onion
  • Yarrow
  • Fescue
  • Milkweed
  • Woodland strawberry
  • Goldenrod
  • Phacelia
  • Borage
  • Douglas Aster
  • Lupine
  • Daisy
  • Mallow
  • Dogwood
  • California poppy
  • Columbine
  • Meadow foam
  • Yellow eyed grass
  • Cinquefoil
  • Blue eyed grass
  • Currant
  • Crabapple
  • Blue elderberry
  • Anise hyssop
  • Coreopsis
  • Spirea
  • Mock orange
  • Serviceberry
  • Trillium
  • Coneflower
  • Snowberry
  • Oregon grape
  • Shore pine
  • Maple
  • Pearly everlasting
  • Globe thistle

 

It’s been a busy month in the Garden Ecology Lab.

  • Gail’s manuscript on bees in home and community gardens has been published in Acta Hort. Briefly, the results of this literature review are that: 213 species of bee have been collected from a garden habitat; gardens have fewer spring-flying and fewer ground-nesting bees, compared to non-garden sites; I suspect that over-mulching might be cutting out habitat for ground-nesting bees in gardens.
  • Aaron presented his first Extension talk to the Marion County Master Gardeners. This 90-minute talk was an overview of using native plants in home gardens.
  • The entire lab is getting ready to present their research results at the 2018 Urban Ecology Research Consortium annual conference, to be held in Portland on February 5th. A few highlights of our presentations, can be found below.

Gail’s Poster on Urban Bees: we sampled bees from 24 gardens in the Portland Metro area (co-authored with Isabella and Lucas)

  • Langellotto and Messer UERC 2018 Poster: click to see preliminary results
  • Most of the bees that we collected await identification. We did find a moderate relationship between lot size and bee abundance: larger yards hosted more bees. But, we also found evidence that suggests that intentional design can influence bee abundance: one of our smallest gardens (site 56 = 0.1 acre), located in the Portland urban core (surrounded by lots of urban development) had the second largest number of bees (42), of the 24 gardens sampled. This garden was focused, first and foremost, on gardening for pollinators. The plant list for this garden (photos, below) includes: borage, big-leaf maple, anise hyssop, globe thistle, California poppy, nodding onion, yarrow, fescue, goldenrod, Phacelia, Douglas aster, lupine, mallow, columbine, meadow foam, yellow-eyed grass, blue-eyed grass, coreopsis, snowberry, Oregon grape, trillium, mock orange, pearly-everlasting, serviceberry, coneflower, blue elderberry, currant, milkweed, dogwood, shore pine, crabapple, cinquefoil.

 

 

 

 

 

 

 

 

Mykl’s Poster on Urban Soils: we sampled soils from 33 vegetable beds across Corvallis and in Portland (co-authored with Gail)

  • All gardens were tended by OSU Extension Master Gardeners.
  • Gardens were over-enriched in several soil nutrients. For example, the recommended range for Phosphorus (ppm in soil) is 20-100 ppm. Garden soils averaged 227 ppm. The recommended range for Calcium is 1,000-2,000 ppm, but the mean value for sampled beds was 4,344 ppm.
  • Recommended ranges gleaned from OSU Extension Publication EC1478.
  • There was a tendency for soils in raised beds to be over-enriched, compared to vegetables grown on in-ground beds.
  • Data suggests that gardeners are annually adding additional soil amendments or compost, and that there has a build up of certain elements in the soil.

Aaron’s Talk on Native Plants: measured bee visitation to 23 species of native and 4 species of non-native garden plants (co-authored with Lucas)

  • Field plots established at the North Willamette Research and Extension Center
  • In the first year of establishment, of the 27 flowering plants that were the focus of this study, seven natives (lotus, milkweed, camas, strawberry, iris, sedum, blue-eyed grass) one non-native (Lavender) did not bloom, or else did not establish
  • Several natives attracted more bees than even the most attractive non-native (Nepeta cataria, or catmint). These include:
    • Gilia capitata: Globe Gilia
    • Madia elegans: Common Madia
    • Aster subspicatus: Douglas’ Aster
    • Solidago candensis: Goldenrod

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.

A native been rolls around inside of a California poppy at the North Willamette Research and Extension Center.

Having moved to Oregon from Michigan this past spring, one of my first memories of the state was the explosion of bright orange and yellow flowers lining the interstate and covering the hills. These ubiquitous flowers were, of course, California poppies (Escscholzia californica). Native to a range covering southern Washington south to the Sonoran Desert, the plant has spread throughout most of North America and onto other continents thanks to human intervention (1). This should come to no surprise to those familiar with the plant, because it is easy to grow and thrives in average soil, as long as drainage is good and there is plenty of sun (3).

California poppies can be grown as perennials or annuals, depending on the severity of the winters (3). The grey-green, finely divided foliage erupts with brightly colored flowers in the spring, but can continue flowering across the growing season if conditions are favorable (1). Long, spindly seed pods appear quickly following pollination and, once dry, easily explode, spreading baby poppies up to six feet away from the parent plant (1). If you’re looking to add these beauties to your own garden, it is best to spread seeds on the surface of the soil in the fall to ensure that dormancy is broken (1). But gardener beware: once established, California poppies are around for the long haul (3).

These flowers have been grown or collected for hundreds of years by the societies that have encountered them (1). Indigenous North Americans first used the plants for a variety of medicinal purposes and the plant quickly rose to fame in Victorian gardens after it was collected by David Douglas for the Royal Botanical Society of England in 1836 (1, 3). Western medicine has also found use of the California poppy, isolating over 30 chemicals for uses ranging from anti-bacterial agents to the treatment of cancer (1). For horticultural purposes, the Royal Horticultural Society today recommends planting along borders, for cut flowers, to create a sense of informality as in a cottage garden, as well as for gravel and rock gardens (4).

The act of gardening is unique in that it strikes a balance between control of and surrender to the natural world. On the one hand, the plants we decide to grow on our little slices of paradise are an irrevocable extension of us and our own stories; however, these plants have their own stories to tell and they transform us into participants of these stories whether we are willing or not. I’ve never heard anyone say, for example, that they planted such-and-such prize-winning hosta to attract deer to their garden. Yet, when these majestic 150-pound creatures sneak silently into our yards for a midnight snack, it’s hard to argue they weren’t invited. The plants we choose act as our ambassadors to a biotic world just beyond our grasp, providing food and habitat for a full spectrum of wildlife. On a larger scale, the landscapes we cultivate can collectively affect everything from water resources to the climate.

While it’s true that I’ve never heard anyone say they are planting for the deer, us gardeners have certainly taken a liking to another sort of creature. The insects of the Anthophila clade, otherwise known as the bees, have found a special place in our hearts. Maybe writer Michael Pollan was on to something when he recognized, in The Botany of Desire, the mirrored way in which the bees visiting his garden had found themselves in the servitude of the plants just as he was. While the gardener tends to the plants’ every need, the bee unwittingly ensures their reproductive success by transporting pollen from flower to flower. Or maybe its the recognition that we ultimately depend on pollinators for our own food security and survival. Whatever the underlying cause behind our species’ admiration of bees, cultivating a diversity of flowers is the surest way to invite them to and help them persist in our landscapes.

A syrphid fly pays a visit to a California poppy at the North Willamette Research and Extension Center.

Whether you sow the seeds of the California poppy simply for its beauty, for its natural history, to help prevent erosion, or for any other reason, you will also inevitably be providing a source of food for our favorite insects, the bees. Surprisingly California poppies don’t provide nectar for pollinators, just pollen, but they are still heavily visited by our native bumblebees, sweat bees, and mining bees, as well as the European honey bee (Apis mellifera) (1, 2). They are also visited by beautiful butterflies, beneficial minute pirate bugs, and glistening beetles (1). Additionally, from our observations at the North Willamette Research and Extension Center, I can personally attest to the California poppy’s popularity amongst a variety of syrphid flies.

As a student interested in creating functional habitat for both humans and wildlife, it truly matters little to me on its face if a plant is native or not. Gardens consisting of native plants can be just as gorgeous and moving as gardens consisting of exotic species — this is true. What does matter to me are the relationships these plants have with other organisms, and what that looks like in a world increasingly and unavoidably modified by humans. So, whether or not you decide to bring the California poppy or any other native plants into your own garden, I hope you do feel inspired to think about these plants in terms of their role in the wider community of life with which we share this planet.

Sources:

  1. Smith, C. 2010. Plant guide for California poppy (Eschscholzia californica). USDA-Natural Resources Conservation Service, Plant Materials Center. Lockeford, CA 95237.
  2. Garvey, Kathy Keatley. “Why Honey Bees Forage in California Poppies.” Bug Squad: Happenings in the Insect World, University of California, 18 Mar. 2014, ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=13179.
  3. Nelson, Julie. “California poppy (Eschscholzia californica).” Plant of the Week, USDA Forest Service Rangeland Management & Vegetation Ecology – Botany Program, www.fs.fed.us/wildflowers/plant-of-the-week/eschscholzia_californica.shtml.
  4. “Eschscholzia californica.” Royal Horticultural Society, www.rhs.org.uk/Plants/106119/Eschscholzia-californica/Details.
Image source: https://www.flickr.com/photos/12567713@N00/2809146063

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.

A common and much-beloved Northwest native, the Douglas aster, happens to be a bit of a misnomer. This profusely blooming, purple-flowered perennial isn’t a member of the Old World Aster genus, but rather belongs to the New World Symphyotrichum (2). As such, our Douglas aster (Symphyotrichum subspicatum) is closely related to its East Coast look-alike, the New England aster (Symphyotrichum novae-angliae), and evidence suggests the two descend from a common ancestor (2).

Naming conventions aside, the Douglas aster should be noted for offering an impressive, season-long (July – September) display of attractive, disk-shaped, and papery flowers while asking for little in return. Like many of the other native plants I have written about to this date, this plant is incredibly hardy and will spread via creeping rhizomes if given the opportunity (3). The USDA Natural Resources Conservation Service recognizes the Douglas aster as being abundant and present from Alaska to California, and into Idaho and Montana (1). In the wild, it is noted as being found in forests, along the banks of streams, and even along the coast (3).

In Oregon gardens, west of the Cascades, the Douglas aster will again require little in terms of care once established. It does prefer full-sun, and well-drained soil, but it similarly thrives in wetland areas (4). Our test subjects in the field faced many hardships, ranging from drought to over-zealous mowing, and still ended up thriving. Therefore, as with the majority of the native plants written about here, this plant may not be appropriate for every garden or indeed for every gardener. The most exciting part about the Douglas aster, however, is not its robust growth habit; but rather, its potential to benefit wildlife and therefore our suburban and urban environments.

In the field, other members of the Asteraceae family (think goldenrod and pearly everlasting) have anecdotally been some of the most popular plants in terms of pollinating visitors, and our Douglas aster plots were no exception. At times, it was hard to keep track of just which insects had or had not been counted during our five minute observations due to their sheer abundance. Thanks to the long bloom period, it was also exciting to the see the progression of pollinators develop as the season passed week by week, and the species composition gradually changed. While the Douglas aster is noted for its attractiveness to many species of butterflies, our observations could suggest that is similarly attractive to a fairly wide array of bees as well (4).

Sources:

  1. “Plant Profile for Symphyotrichum subspicatum subspicatum (Douglas aster).” Plants Database, USDA NRCS, plants.usda.gov/core/profile?symbol=SYSUS.
  2. Candeias, Matt. “How North America Lost Its Asters.” In Defense of Plants, 12 Oct. 2016, www.indefenseofplants.com/blog/2016/10/12/how-north-america-lost-its-asters.
  3. Knoke, Don, and David Giblin. “Symphyotrichum subspicatum.” WTU Herbarium Image Collection, Burke Museum of Natural History and Culture, biology.burke.washington.edu/herbarium/imagecollection.php?Genus=Symphyotrichum&Species=subspicatum.
  4. “Douglas Aster.” Washington Native Plant Society: Starflower Image Herbarium, 5 Nov. 2007, www.wnps.org/landscaping/herbarium/pages/aster-subspicatus.html.
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.

*************************************

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.