Top 10 Oregon Native Plants for Pollinators: Week 9

The Garden Ecology Lab’s Pollinator Plant PR Campaign Presents….. California Poppy!

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 9! Profiles will include photos, planting information, and will highlight common pollinators of each plant.

Bumblebee visits California poppy. Photo by Jen Hayes.

Plant Facts

  • Scientific Name: Eschscholzia californica
  • Life Cycle: Annual/Perennial
  • Growth Habit: Clumping, sprawling
  • Bloom Duration: Early Spring to Late Summer depending on seeding date.
  • Hardiness Zone: 7-10
  • Special Traits: Drought-tolerant, deer and rabbit resistant.
  • When to plant: Seed in Fall for a Spring bloom, or seed in Spring for a mid-summer bloom.

Pollinator Facts

  • California poppy only provides pollen to its insect visitors, but provides it in an abundance!
  • Aaron’s study found California poppy to be associated with 4 species of sweat bees: Halictus farinosus, H. tripartitus, Lasioglossum dialictus sp. 5, L. olympiae, and a bumblebee: Bombus vosnesenskii.
  • Other common visitors to California poppy include butterflies, specifically, acmon blue and mormon metalmark.

Sweat bee leaving a California poppy. Photo by Jen Hayes

California Poppy’s Native Range in Oregon

Oregon's populations of California poppy are primarily found in the Willamette Valley and the Klamath Mountains as well as some parts of the Columbia River Gorge and the Coast Range.

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

California poppy as a pollinator plant

California poppy’s range extends from Washington to northwest Baja California and east towards Arizona and southwest New Mexico. A popular flower for roadside plantings, California poppy survives well in average to poor soil that is well-draining. It survives mild-winters as an herbaceous perennial and reseeds itself readily. California poppy is an all-around easy pollinator plant to grow, and growing it pays off, as it attracts an incredible diversity and abundance of bees with its remarkable volumes of pollen.

Infographics developed by LeAnn Locher, Aaron Anderson, and Gail Langellotto.

Did you know?

California poppy’s petals are responsive to light! In the absence of light (at night and on cloudy days) petals spiral around each other and tighten to a close. In the presence of light, cells in the petals expand in response to the plant growth hormone auxin. This mechanism opens the petals allowing pollinators to access the flower’s pollen — although in the field we watch impatient bumblebees force their way into closed California poppy flowers to get to the pollen anyways.

Petals close tight during the night and remain so on overcast days. Photo by iNaturalist user metacom CC some rights reserved
Poppies in various stages of opening and poppy buds enclosed in pinkish-green calyxes. Photo by iNaturalist user Daniel Das CC some rights reserved

Photos from the field

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

Top 10 Oregon Native Plants for Pollinators: Week 8

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.

Photo by iNaturalist user © slewiiis,
 some rights reserved

Plant Facts

  • Scientific Name: Gilia capitata
  • Life Cycle: Annual
  • Growth Habit: Erect, clusters
  • Bloom Duration: May – June
  • Hardiness Zone: 7-10
  • Light requirements: full sun
  • Special Traits: Drought tolerant, tolerant to various soil types.
  • When to plant: Seeds can be sewn directly in the fall, or can be stratified indoors over the winter before planting out in the spring.

Pollinator Facts

  • Globe Gilia provides both nectar and pollen to its insect visitors.
  • Gilia was found to be associated with the yellow-faced bumble bee, Bombus vosnesenskii in Aaron’s research.
  • Globe Gilia is also a larval host for at least one moth species, Adela singulella, but possibly four others as well.
  • In addition to insect visitors, Gilia is can be an occasional nectar source for hummingbirds1, which love its tubular flowers!

Photo by iNaturalist user © mudcitymelissa,
 some rights reserved

Globe Gilia‘s Native Range in Oregon

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.


Did you know?

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.

Now back to Globe Gilia: Photos from the field

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

Top 10 Oregon Native Plants for Pollinators: Week 7

The Garden Ecology Lab’s Pollinator Plant PR Campaign Presents….. Farewell-to-Spring!

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 7! Profiles will include photos, planting information, and will highlight common pollinators of each plant.

Photo by Jen Hayes.

Plant Facts

  • Scientific Name: Clarkia amoena
  • Life Cycle: Annual
  • Growth Habit: Upright, clumping
  • Bloom Duration: June – September
  • Hardiness Zone: 1-11
  • Special Traits: Drought tolerant, deer resistant
  • When to plant: For best results, direct seed in Fall or early Spring. Seeds can also be sown in containers or cold frames in the winter.

Pollinator Facts

  • Farewell-to-Spring was found to be associated with Megachile brevis, a species of leafcutter bee.
  • Other common bee visitors include long-horned bees of the genus Eucerini and other species of leafcutter bees.
  • Farewell-to-Spring also hosts some butterflies and moths including the White-Lined Sphinx, Pacific Green Sphinx Moth, and Clark’s Day Sphinx Moth.
  • Farewell-to-Spring provides both nectar and pollen to its insect visitors.
  • Although pollen is easily accessed on the protruding stamen, bees must dive into the flower to reach the nectar that is produced beneath the petals. This is because nectar is produced at the base of the ovary, and Farewell-to-Spring has an “inferior ovary” meaning the ovary is positioned below the sepals and petals.

A male bumble bee dives into a Farewell-to-Spring flower to reach its nectar. Photo by Jen Hayes.
Farewell-to-Spring’s nectaries are found beneath the stamen and petals. Photo © Stephanie Hazen.
 some rights reserved

Farewell-to-Spring’s Native Range in Oregon

Farewell-to-Spring is found throughout Western Oregon from the Coast through the Cascades. Oregon is home to 4 subspecies of Clarkia amoena.

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

Farewell-to-Spring as a pollinator plant

Farewell-to-Spring hosts a moderate abundance of bee visitors, but the diversity of bees it hosts is among the highest found in the study! With a long flowering season, Farewell-to-Spring blooms when spring wildflowers are beginning to turn brown. Bloom duration can be lengthened by occasional watering over the summer, although Farewell-to-Spring are drought-tolerant and survive with minimal summer irrigation. This flower is an annual, but will reseed itself readily.

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.


Did you know?

Leaf cutters forage for pollen, nectar, and one more potentially surprising resource: petal clippings! Using their mandibles, the bees cut out of a piece of a petal (often in the shape of a crescent), clasp the piece of petal under their abdomens, and fly away to use the piece as building material in their nests. If you keep a mason bee or leafcutter bee house in your yard and grow Farewell-to-Spring, look for nest holes that are plugged with pink petals instead of mud or leaves.

The tips of some of this flower’s petals have been harvested from by leafcutter bees:


Leafcutters in Action

In each of Jen’s two field seasons, she has set a challenge for student technicians: obtain a video of a leafcutter harvesting a piece of petal from Clarkia. Students that win the challenge are rewarded with baked goods!! This past summer, Mallory succeeded in capturing not one, but two videos of leafcutters in action (below). Leafcutters can be particularly difficult to capture on video because they cut the petal pieces very quickly, and often fly even faster! If you have Clarkia growing in your garden, look to see if your flowers bear any crescent-shaped cuts. If they do, you too might be able to spot some special bees flying away with their floral confetti.

Videos by Mallory Mead, summer 2021.

Photos from the field

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

Top 10 Oregon Native Plants for Pollinators: Week 6

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.

Photo © Rob Irwin
 some rights reserved

Plant Facts

  • Scientific Name: Madia elegans
  • Life Cycle: Annual
  • Growth Habit: Erect, slender
  • Bloom Duration: July – September
  • Hardiness Zone: 1-11
  • Light requirements: Prefers full sun, will tolerate partial shade.
  • Special Traits: Drought tolerant, deer resistant, seeds valued by birds, adaptable to many soil types and textures.
  • When to plant: Seeds can be sown directly in the fall, or sown in containers or cold frames in the winter. Stratify seeds if growing indoors.

Pollinator Facts

  • Common madia provides both nectar and pollen to its insect visitors and blooms during a period where foraging resources are often scarce (late summer – early fall).
  • Madia was found to be associated with two bee species in Aaron’s research: the Bi-colored Sweat Bee (Agapostemon virescens) and Titus’s Sweat Bee (Lasioglossum titusi)
  • Madia is also the larval host for three moth species: the Spotted Straw Sun Moth (Heliothis phloxiphada), the Small Heliothodes Moth (Heliothodes diminutivus), and an Epiblema moth (Epiblema deverrae)1.

Photo © Chris Cameron
 some rights reserved

Common Madia‘s Native Range in Oregon

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.


A syrphid fly visiting a Madia flower. Photo by Signe Danler.

Did you know?

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.

Photos from the field

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

Top 10 Oregon Native Plants for Pollinators: Week 5

The Garden Ecology Lab’s Pollinator Plant PR Campaign Presents….. Canada Goldenrod!

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 5! Profiles will include photos, planting information, and will highlight common pollinators of each plant.

Photo by iNaturalist user jessdraws.
no rights reserved (CCO).

Plant Facts

  • Scientific Name: Solidago canadensis*
  • Life Cycle: Perennial
  • Growth Habit: Erect, arching
  • Bloom Duration: July-October
  • Hardiness Zone: 3-9
  • Special Traits: Moderately drought tolerant, deer and rabbit resistant
  • Light requirements: Prefers full sun, but tolerates some shade.
  • When to plant: Plant starts in the Spring, or sow seeds directly in the Fall.

Pollinator Facts

  • Canada goldenrod provides both nectar and pollen to its insect visitors.
  • In Aaron’s research, Canada goldenrod was found to be associated with a species of long horned bee, Melisoddes microstictus and bees from the genus Bombus (bumblebees).
  • Other common visitors to Canada goldenrod are Northern Checkerspot butterflies, Field Crescent butterflies, Wavy-Lined moths, and Common Grey moths.
Bumble bee visiting Canada Goldenrod. Photo by Signe Danler

*A Note on Taxonomy

Canada goldenrod is often treated as a complex, or group of species, under the scientific name Solidago canadensis. In western North America, the complex includes S. elongata, S. lepida, and S. altissima. Tall goldenrod, S. altissima, is not native to Oregon, so when we refer to Solidago canadensis in Oregon, this only includes S. lepida “Cascade Canada Goldenrod” and S. elongata “Western Goldenrod”.

Goldenrods (the genus Solidago) are known to be a very difficult plant to identify to species, because they have a great amount of variation in their morphology within even a single species. To avoid any concerns about what species you’re getting when sourcing goldenrod or other native plants, we highly recommend purchasing plants from a local native plant nursery or grower that sources their seeds within your region!

Canada Goldenrod’s Native Range in Oregon

Oregon is home to Solidago lepida "Cascade Canada Goldenrod" and Solidago elongata, "Western Canada Goldenrod". Both of these species are found throughout Oregon, though they were previously thought to be geographically distinct.

Maps and legend acquired from the Oregon Flora Project, with Imagery Sourced from Google.

Canada Goldenrod as a pollinator plant

Canada goldenrod grows in prairies, meadows and riparian areas across Canada and the United States. Great for erosion control, hedgerows and pollinator gardens, Canada goldenrod will fill space with hardy foliage year round and present a showy display of golden flowers in the late summer. The pyramidal inflorescences are lined with tiny composite flowers that brim with nectar and pollen. Goldenrod supports many late season butterflies, moths, bees, beetles and some wasps.

Goldenrod is a wonderful late-flowering plant for pollinators; it hosts a moderate abundance and a high diversity of insect visitors. During its peak bloom, you can often find numerous different insects foraging on goldenrod. We love combining goldenrod with Douglas aster for a beautiful late-season floral display of yellow and purple, though it also compliments shorter annual species as well.

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?

Although this goldenrod is often blamed for people’s late summer allergies, the culprit is in fact ragweed! Ragweed and goldenrod have different pollination styles: ragweed produces masses of airborne pollen in an attempt to reach other ragweed plants by wind. Since goldenrod has evolved with pollinators to carry its pollen in a targeted fashion, goldenrod produces less pollen, very little of which is airborne.

Canada goldenrod has additionally been used as a plant medicine in many cultures; it was used as a substitute for English tea during the American Revolution for its pain-relieving and diuretic effects. Goldenrod flowers are edible and make a colorful garnish that make a beautiful addition to garden salads.

Photos from the field

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

Top 10 Oregon Native Plants for Pollinators: Week 4

The Garden Ecology Lab’s Pollinator Plant PR Campaign Presents….. Varileaf Phacelia!

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 4! Profiles will include photos, planting information, and will highlight common pollinators of each plant.

Photo by iNaturalist user Leslie Flint.
CC Some rights reserved.

Plant Facts

  • Scientific Name: Phacelia heterophylla
  • Life Cycle: Biennial/ annual, typically grown as an annual in Oregon
  • Growth Habit: Upright, mounding
  • Bloom Duration: April – July
  • Hardiness Zone: 3-7
  • Special Traits: Shade tolerant, drought tolerant
  • Light requirements: Full sun to part shade
  • When to plant: Seeds should be sown in the fall, starts may be planted in the fall or spring after the last chance of frost.

Pollinator Facts

  • Varileaf Phacelia provides both nectar and pollen to its insect visitors.
  • Phacelia was found to be associated with five bee species in Aaron’s research: the obscure bumblebee (Bombus caliginosus), Edward’s long-horned bee (Eucera edwardsii), the fuzzy-horned bumblebee (Bombus mixtus), the confluent miner bee (Panurginus atriceps), and the yellow-faced bumblebee (Bombus vosnesenskii).
  • Phacelia is also a larval host for 4 moths: the Bilobed Looper Moth (Megalographa biloba), the Geranium Plume Moth (Amblyptilia pica), the Orange Tortrix Moth (Argyrotaenia franciscana) and Clepsis fucana1.

Photo by Aaron Anderson

Varileaf Phacelia‘s Native Range in Oregon

Phacelia heterophylla is native to most of the Western United States – From Washington to California, east to Montana and south to New Mexico. It is additionally native to Canada, where it is currently considered “imperiled” by the IUCN red list2.

Varileaf Phacelia's native range covers nearly the entire state of Oregon! It's native habitat includes moist conifer forests, riparian areas, sagebrush, mountain brush, as well as in aspen and fir communities3.
Maps and legend acquired from the Oregon Flora Project, with Imagery Sourced from Google.

Varileaf Phacelia as a pollinator plant

A female long-horned bee (Eucera sp.) searches for some leftover forage on a spent Phacelia heterophylla inflorescence. Photo by Aaron Anderson.

Varileaf Phacelia is the epitome of an underappreciated pollinator plant! This annual with petite white flowers attracts both an abundance and diversity of insect visitors. With stamen that stick out of the corolla, it heavily advertises its nutritious rewards, attracting plenty of busy bees. In fact, it commonly hosted 5 different bee species in Aaron’s field surveys, including three charismatic bumblebee species, one of which is currently listed as “vulnerable” on the IUCN Red List: Bombus caliginosus, the obscure bumblebee4.


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.


In a survey of gardeners conducted by Aaron and the Garden Ecology Lab, Phacelia heterophylla ranked last among 23 native plants scored for their aesthetic appeal. It may appear “weedy” to some gardeners, but as an annual, it could easily be interspersed with more attractive annual face flowers (such as California poppy, meadowfoam, farewell to spring, or baby blue eyes) to create a colorful and nutritious pollinator garden. Varileaf Phacelia is also a great native annual to include in dryland pollinator gardens, considering it is drought tolerant and able to grow in both nutrient poor and rocky soils.

Did you know?

Photo by iNaturalist user jwlipe. CC Some rights reserved.

Varileaf Phacelia also has the common name "Variegate Scorpionweed", and the pictures above can show you exactly why! It's flowers are borne on elongated stems which are tightly curled, similar to a fiddlehead from a fern! The flowers bloom from the base to the apex of the stem, and the "scorpion tail" slowly unravels as the blooms travel up the stem.

Photos from the field

Of all of the plants we highlight in this 10-week series, Varileaf Phacelia is the one plant that Gail regularly says is in great need of it's own public relations (PR) team. The goal of these plant profiles is to share information and photos of these plants that might convince readers to love this plant as much as we (and the bees) do! 

Let us know which plants have caught your eye, or those that may still take some convincing, by leaving a comment below! 🐝

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

Top 10 Oregon Native Plants for Pollinators: Week 3

The Garden Ecology Lab’s Pollinator Plant PR Campaign Presents….. Pearly Everlasting!

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 3! Profiles will include photos, planting information, and will highlight common pollinators of each plant.

Photo by Patrick Perish

Plant Facts

  • Scientific Name: Anaphalis margaritacea
  • Life Cycle: Perennial
  • Growth Habit: Upright, clumping
  • Bloom Duration: June – October
  • Hardiness Zone: 3-8
  • Special Traits: Drought tolerant, deer resistant
  • Light requirements: Prefers full sun but will grow in partial shade
  • When to plant: Plant starts in the Spring, or sow seeds directly in the Fall.

Pollinator Facts

  • Pearly everlasting was found to be associated with two species of mining bees in Aaron’s research: Andrena cerasifolii, Andrena candida.
  • Other common visitors to Pearly Everlasting are American Lady butterflies, Painted Lady butterflies, Everlasting Tebenna moth, and Sweat bees.
  • Female and male flowers are generally found on separate Pearly Everlasting plants. This means that male plants provide nectar and pollen to insect visitors while female flowers just provide nectar.
Andrena visiting Pearly Everlasting. Photo by Aaron Anderson

Pearly Everlasting’s Native Range in Oregon

Oregon is home to three varieties of Pearly Everlasting whose native ranges extend the Cascade range, Western Oregon and parts of northeastern Oregon.

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

Pearly Everlasting as a pollinator plant

Pearly Everlasting is an herbaceous perennial commonly seen in open meadows, burned areas, rocky flats and along roadsides in dry, sun-exposed soils. Native throughout the United States, except for the Southwest, Pearly everlasting is an excellent nectar resource for pollinators, and is especially attractive to many butterfly and moth species. It makes an important larval host plant for American Lady and Painted Lady Butterflies whose seasonal feeding can leave Pearly Everlasting foliage slightly tattered, but nothing that the plant can’t recover from.

Pearly Everlasting hosts a moderate abundance and a relatively low diversity of insect visitors, but is a key host plant for its associated pollinators.

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?

As a plant that thrives in high light and very dry conditions, Pearly Everlasting is one of the first plants to colonize recently burned forests. When rain comes after a fire-season, Pearly Everlasting sends out rhizomes that allow the plant to spread rapidly across nutrient-rich areas. Similarly in a garden setting, Pearly Everlasting has low moisture and nutrient needs but when heavily watered and fertilized, it can quickly take over.

Established Pearly Everlasting should not be irrigated more than twice per month in the summer months. The white, petal-like bracts of Pearly Everlasting flowers retain a fresh appearance after being dried, so gardeners that allow aboveground growth to dry out in the summer months will be rewarded with dried flowers perfect for floral arrangements.

Photos from the field

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

Top 10 Oregon Native Plants for Pollinators: Week 2

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

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

Top 10 Oregon Native Plants for Pollinators: Week 1

The Garden Ecology Lab’s Pollinator Plant PR Campaign Presents….. Yarrow!

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 1! Profiles will include photos, planting information, and will highlight common pollinators of each plant.

Plant Facts

  • Scientific Name: Achillea millefolium
  • Life Cycle: Perennial
  • Growth Habit: Upright, spreading
  • Bloom Duration: June – October
  • Hardiness Zone: 3-7
  • Special Traits: Drought tolerant, deer resistant
  • When to plant: Starts can be planted in the spring or fall.

Pollinator Facts

  • Yarrow provides both nectar and pollen to its insect visitors.
  • Yarrow was found to be associated with two species of Andrena in Aaron’s research (Andrena cerasifolii, A. candida).
  • Andrena is a genus of early summer mining bees!
  • Other common visitors to yarrow include sweat bees, nomad bees, and butterflies!
  • Yarrow inflorescences provide a great “landing pad” for pollinators- they can rest directly on the plant while they forage.

Yarrow’s Native Range in Oregon

In Oregon, we have our own native variety of yarrow: Achillea millefolium var. occidentalis. 

Western yarrow's native range covers the entire state of Oregon.

Map acquired from USDA Plants Database. Copyright 2014 © ESRI

Yarrow as a pollinator plant

Yarrow is a ubiquitous North American native plant: its range extends from Alaska to Florida and every state and province in between! Though it commonly appears on pollinator planting lists, many people are not convinced that it’s a great bee plant, because it is not typically buzzing with activity like we may see on Goldenrod or Douglas Aster. Instead of hosting an abundance of visitors, yarrow supports a high diversity of insect visitors.

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 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.

Although yarrow doesn’t buzz with activity like some pollinator plants, it’s certainly not a flower to ignore! Yarrow is a hardy and low maintenance perennial that establishes and spreads readily in gardens. It’s a beautiful cut flower and can also be dried to include in longer lasting floral arrangements; its foliage that maintains its aromatic scent even after drying. Yarrow is additionally a wonderful plant medicine that has been used for centuries.

Did you know?

Yarrow has naturally-occurring pink variants! It can vary from pale pink (left), to deeply magenta (right). These plants were started from seeds collected from wild populations of yarrow, so we can be certain it is indeed a natural variation, rather than a true hybrid or cultivar!

Another fun fact: "millefolium" translates to "thousand-leaved", which is a reference to its dissected leaves!

Photos from the field

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

2021 Field Update: Natives & Nativars

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’.