If you are a subscriber to our blog, you have likely seen our photos and videos of one of our favorite plant-pollinator interactions: the petals of Farewell-to-Spring (Clarkia amoena) being harvested by leafcutter bees!
After observing this eccentric harvest behaviorin the research garden, we got curious about the bees behind the petal-nest craft, and how we could study this interaction further.
Leafcutter bee mid-petal-harvest! Photo by Devon Johnson.
Crescent-shaped petal-cuts left behind by leafcutter bees.
iNaturalist is a popular community-supported biodiversity database that the Garden Ecology Lab has been experimenting with in recent years. Jen realized that the leafcutter bees’ distinct crescent-shaped mark are visible in many iNaturalist observations of Clarkia amoena. She wondered how we could use the already sizeable iNaturalist database of Clarkia amoena observations to study the interaction over a wider geographic and chronological scale than that of the research garden. Jen and Gail agreed to mentor me in producing an undergraduate research thesis on this subject.
The study’s objective is to use iNaturalist’s data on Clarkia amoena to see if there is a difference in leafcutter bee usage of Clarkia amoena petals based on whether the flower is a native versus a cultivar type, and whether the flower is found in an urban or non-urban environment.
In this process we have found that iNaturalist is easy for anyone to contribute to, but the information it provides is limited compared to the wealth of contextual information gained when being in the actual, living presence of a specimen. So, to get a greater feel for the intricacies of this flower, I embarked on what we called “Ground-Truthing Field Trips” to check out some Clarkia amoena populations in the “real world”.
I went out during peak pollinator season, following the coordinates of recently posted iNaturalist observations. Each specimen I visited was incredibly different from the next. I found the delicate blossoms in natural areas, the borders of farmland, restoration sites, and gardens.
Data from these trips will not be published in my thesis because the contexts are not exactly comparable, and my sampling was exploratory rather than precise. Nonetheless, I gained contextual insight and inspiration watching diverse pollinator assemblages in beautiful meadows of pink.
Mallory at a meadow restoration site near Corvallis with Clarkia amoena and tarweed (Madia elegans).
The field trips have helped us more clearly see through the window of iNaturalist and have informed the methodology we use.
For example, I saw examples of hybridization between two species of Clarkia in a seeded restoration site, and cultivar-hybrid escapees in natural areas. It’s been important to navigate identification of cultivars and hybrids in iNaturalist.
In a restoration prairie seeded with two different Clarkia species, pollinators cross-pollinate them, giving rise to sterile hybrids (Lewis & Raven, 1958). Note the malformed stigma and anthers.
Simultaneously, our field crew recorded petal-cutting behavior on the Clarkia amoena natives and nativars at Jen’s research garden this summer. Below are the three cultivars in the garden, and if you look closely you can see “petal-cuts” which we counted and recorded weekly. We will analyze the difference in leafcutter usage between the cultivars and native type.
‘Aurora’‘Scarlet’‘Dwarf White’
This hot pink, stripy Clarkia doesn’t look like either the native or cultivars we had planted!
Clarkia amoena is an annual that reseeds itself effectively, so last year’s seeds gave rise to this season’s blooms. To our surprise, however, Clarkia amoena of all different colors started popping up in our research plots this Spring! Last season’s bees had combined pollen from the garden’s varieties bringing rise to all sorts of intermediate forms.
Clarkia amoena is prone to hybridization between members of the species or cultivars in the same proximity. These intraspecific hybrids are fertile. We seek to explore how cultivar genetics may be moving into natural populations.
Through the winter, our team is working with the iNaturalist data to quantify leafcutter bee petal usage.We expect to share our results in June 2023, so stick around to hear about our findings!
Work Cited:
Lewis, H., & Raven, P. H. (1958). Rapid Evolution in Clarkia. Society for the Study of Evolution, 12(3), 319–336.
The sunny days are diminishing as summer rolls into autumn, and as the sun descends, the bees’ flight lulls to rest. Bees sense and respond to light and use the sun to orient themselves and navigate. Along with their two large compound eyes that are used for vision, bees have three simple eyes that sit atop their their heads in a triangular formation. These are called ‘ocelli’ and they sense light.
Originally posted by postgraduate student Hamish Symington, this video shows bees being studied by fellow student Kristina Buch in the Cambridge University Botanic Garden.
Ocelli can be seen atop the head between the compound eyes. Photo of bee from the genus Triepeolus by Mallory Mead.
There is a video circulating the internet of honeybees flying in an enclosure in a laboratory. The video shows the researcher turning off the lights in the enclosure, causing the bees to drop to the ground instantaneously, showing how honeybees will not fly in the absence of light.
We notice similar behavior in the field on days where clouds pass over the sun intermittently. When the sky is bright, our plants bustle with pollinators, and when shadows come over, most bees are suddenly out of sight. It makes sense that as the days get shorter and colder the sight of pollinators will become more and more fleeting!
Some bees are still coming out during the warm October afternoons, and collecting their final energy reserves for the winter. Goldenrod, Douglas’ aster, California poppy, bee balms, and black-eyed Susan, amongst other late blooming pollinator plants are still providing bees with nectar and pollen during this time of transition.
Purple Aster and goldenrod in a natural meadow. Photos by Mallory Mead.
Goldenrod in meadow.
A long horned bee and a sweat bee on black-eyed Susan (Rudbeckia hirta).
Metallic green sweat bee on Scabiosa.
During this season, honeybees and bumblebees predominate the landscape, while long-horned bees (genus: Melisoddes), leafcutter bees (genus: Megachile) and sweat bees (family: Halictidae) can still be seen as they finish up resource collection in the Willamette Valley.
Social bees
Honeybees must make enough honey before temperatures drop and they can no longer leave the hive, so you’ll find them foraging for pollen and nectar as late in the season as possible.
In late summer and fall we begin to see an influx of bumblebee queens. During the summer, the queens are busy reproducing in their underground hives, while worker bees take to the landscape. However, near the end of the foraging season, new queens hatch and fly out to find mates and food. You may see bumblebee queens getting their last bits of food energy before overwintering, while the rest of the colony (males and workers) dwindle away.
Leaf, mud and petal nests are capped and ready for winter! Photos by Mallory Mead.
Petal nest in bamboo.
Many solitary bees are finishing their last nests where they’ve laid eggs for the next generation of their species.
If you care for nest boxes in your garden be sure to take appropriate steps to bring your bees indoors and clean their cocoons. Check out the Linn Master Gardener Association Bee Notesemail list to receive timely emails about the seasonal steps of caring for mason bees.
When solitary adult bees finish reproducing and nest building, their work is done, so they die off. But small carpenter bees, from the genus Ceratina, are an exception. Ceratina females remain as late into the cold season as they can muster in order to guard their nests.1 These protective mothers fend off predators, pests and parasitoids that try to invade the nests.
This fall, we hope you are able to see some of the last glimpses of bees of the year!
This post concludes our series on what the bees are doing right now! Thank you for taking part in this seasonal journey through the lives of bees in the Willamette Valley.
Source Cited:
1: Danforth, B. N., Minckley, R. L., & Neff, J. L. (2019). The solitary bees: Biology, evolution, conservation. Princeton University Press.
Summer is the main active season for many bee species. After a wet spring in Western Oregon, the sun is out and our world is in bloom!
So what are summer bees up to right now? The main events of the season are…
Foraging for nectar and pollen
Finding mates and laying eggs
Excavating, finding and building nests for offspring.
Adult bees also experience predation by spiders and birds during this time. This Crab Spider caught a female long horned bee in its jaws!
A female long horned bee caught by a crab spider on Douglas’ Aster.
So who exactly is out and about in your garden at this time of year?
Bumblebees and honeybees visibly dominate the landscape throughout the summer, but lean in closer to your flowering plants and you’ll find the smaller sweat bees (family: Halictidae), long horned bees (genera: Melissodes and Eucera), leafcutter bees (genus: Megachile) and small carpenter bees (genus: Ceratina). Although there are many others amid the vast diversity of bee species science is only beginning to understand, these are some common garden visitors. We’ll go through each group and their summer activities.
Notice the two adomenal segments beneath the yellow stripe of this male yellow-faced bumblebee(Bombus vosnesenskii). Photo by Jen Hayes.
The presence of pollen on a bee especially carried in pollen baskets, is a good indicator that the bee is a female. Photo by Jay Stiller-Freeman
Bumblebees: By summertime, most queens have established colonies of workers who do the foraging for the hive, so we see less large queen bumblebees and more smaller workers as the season progresses. Later in the season, queens lay male eggs as well as eggs for the next generation of queens. Male bumblebees take to the landscape in mid to later summer, recognizable by their additional segments on their abdomen, long antennae, and by the fact that they don’t carry pollen like females do. Males do not have stingers, so if you can confidently identify male bumblebees, they are fun to play with while they’re waiting around for new queens with which to mate. You’ll find them sipping on nectar-rich plants like lavender, herbs, asters and heal-all.
Honeybees: Summer is prime time for honeybees! Worker populations are at their peaks; pollen and nectar are flowing. As hive population size rises and available hive space remains static, honeybees may organize a swarm. In this process, the current queen lays new queen eggs and part of the colony joins her to lift off and leave the colony in search of a new cavity to make their home. Swarming is considered a form of colony-level reproduction supporting the idea that honey bee colonies are super organisms. Swarming is common in spring and early summer. Beekeepers add new boxes to hives so prevent their colonies from swarming.
Late summer is mating season for honey bees. Males and new queen eggs are laid and emerge to mate with individuals from other colonies. Honeybees mate in the air at heights ranging between 15 and 60 m1.
A yellow-faced bumble bee and a honey bee sip nectar from lavender. Photo by Devon Johnson.
Sweat bees
Sweat bee on California Poppy ‘White’. Photo by Tyler Sato Spofford.
A halictid dear to our hearts at the Garden Ecology Lab is the metallic green bee (genus: Agapostemon). While females provision nests in the soil, you can find males resting in congregations on flowers in the evening time and early morning!
Sweat bees are one of the most common groups of “small” bees you’ll find in your garden. They forage on a wide variety of plants and come in a wide range of sizes, but most have striped abdomens, and all carry pollen on their hind legs and nest in soil.
Agapostemon virescens male congregation.
A male long horned bee from the genus Eucera on a California Poppy ‘Purple Gleam’. Photo by Jen Hayes.
Long Horned bees
Long horned bees are most active on our research plots in the mid to late summer. I love this group because they are so easy to recognize. Males have antennae that are way longer than other bees’ relative to their bodies. The females, who bear antenna of normal lengths, are still easy to spot because they have long feathery scopa (or hairs) on their hind legs for collecting pollen that they absolutely pack with pollen while foraging.
Long horned bees are sometimes referred to as “sunflower bees” for their love of foraging on sunflowers.
Long horned bees nest in the soil2, so when you see them take it as a reminder to leave some uncovered, undisturbed soil in your garden for these bees to persist!
Notice this female long horn’s feathery pants! Photo by Mallory Mead.
A relatively large small carpenter bee. Photo by Mallory Mead.
Small Carpenter bees
When I point out small carpenter bees (genus: Ceratina), most of my friends can’t believe they are bees. They think they are some kind of flying ant. Their bodies are sleek, and often shimmer with a green or blue reflective gleam.
Small carpenter bees are considered wood excavators as they dig out the pith from dry plant canes for their nests. Ceratina are a unique group in terms of their parenting style. Unlike other solitary bee mothers, Ceratina mothers guard their offspring even after their offspring have developed into adults. Mothers stick around as long as they can until Winter falls.2
Leafcutter bees
Leafcutter bees (genus: Megachile), as their names suggest cut leaves from their host plants! They use these bits of leaves to line their ground and cavity nests, to waterproof and protect their offspring.
Leafcutter bees are from the bee family Megachilidae, a family known for creative nest building. Bees in this family were supposedly able to expand their ranges due to their flexibility in nesting site and material. They’ve been found nesting in wood, porous stones, stems, galls, and even snail shells filling these various cavities with leaves, mud, plant resins, pebbles, straw and even petals2. The fascinating nest building behavior we’ve gotten to witness in the field is petal cutting of Farewell-to-Spring (Clarkia amoena) blooms.
We can track the usage of Farewell-to-Spring petals by leafcutter bees due to the signature crescent shape left behind on the flowers.
Thank you for joining us on this exploration of some of Oregon’s summer bees and what they are currently doing! We will release one more blog post in this series. Be sure to subscribe so you don’t miss the next in the series!
It’s early spring and the trees have begun leafing out. Colorful flowers are springing from the ground, and the landscape is slowly coming to life with insect activity. In this post, I’ll highlight some of Oregon’s ubiquitous spring bees, what they are up to, and how to easily recognize them.
Graphic by Jen Hayes
Queen bumblebees are emerging from their winter burrows under leaf litter and forest duff. They zoom by with boisterous buzzes. Queen bumblebees are sturdy and furry, and can power through wind, rain and cold better than any other type of bee. Queens are much bigger than the workers that will come once the queens find nest sites and begin laying eggs. For now, they work alone, preparing to lay their first set of worker eggs.
If you see (or hear) any queen bumblebees this spring as they scan the sparsely blooming landscape, they are most likely looking for a proper nest site, finding nectar to energize this search, or, if one has already found her nest, she may be collecting pollen to feed her developing worker offspring.
A rain-drenched Yellow-faced bumble bee on Oregon Grape. Photo by Jen Hayes.
A female mason bee has brought bright yellow pollen to her nest. Video by Jen Hayes.
Mason bees (Osmia lignaria) are a cherished Oregon spring bee active from March to early June. Look closely in a bee hotel for a chance to observe mason bees in action!
Male mason bees emerge first from their pupal cocoons. You might see them patrolling bee hotels waiting for a female to chase down. When the females emerge a little later, they mate and then begin their work provisioning nests with pollen balls and eggs. An individual female has a short lifespan living only about 20 days, but in this time, she may provision anywhere from 2 to 7 nest holes each containing many offspring cells.1 Quite the busy bee!
Andrena is a genus of mining bees that are some of the earliest risers when it comes to spring emergence. They are a diverse group of small, furry, ground-nesting bees that are only active for a few weeks out of the year. Andrena are solitary bees, but can be seen foraging and mating in droves on early blooming fruit trees like cherry, apple and pear. Last spring, I watched hundreds swarm this cherry tree to collect nectar and mate.
Andrena in cherry tree (captured with magnifying lens). Photo by Mallory Mead
Andrena mating pair. Photo by Mallory Mead.
Spring Bee Quick ID:
Now, let’s identify some of the bees you may see out and about on sunny spring days when the wind is low. We’ll start with the most conspicuous group – the bumblebees. Bumblebees are the biggest and the loudest bees on the landscape, covered in a thick coat of fuzz. Here’s how to recognize the 3 most common species of bumblebees you’ll see in the Willamette Valley in early spring.
Bombus vosnesenskii or the “yellow-faced bumblebee” is by far the most common bumblebee in this region. It is recognized by the yellow fuzz on its face and yellow band near the distal end of its abdomen.
B. vosnesenskii foraging on butterfly bush. Photo by Mallory Mead.
B. melanopygus queen foraging on Wartleaf Ceanothus. Photo by Mallory Mead.
Bombus melanopygus, the “black-tailed bumble bee” is another of the earliest Bombus species to emerge. You can identify this bee by the orange band in the middle section of its abdomen!
Bombus mixtus, the “fuzzy-horned bumblebee”, tends to emerge a little later than the previous two species, and has orange hair on its lowest abdominal segments.
B. mixtus flies amid borage plant. Photo by Mallory Mead.
Mason bees can be recognized by their deep iridescent blue-green color, that sparkles in the sun. Males are distinguished from females by their small size and the yellow mustaches found on the front of their faces. Females lack the yellow tufts and are larger than the males but smaller than a honey bee. They carry pollen on the underside of their abdomen which is a trait unique to their bee family, Megachilidae.
Female mason bee. Photo by Jen Hayes.
Male mason bee. Photo by Mallory Mead.
Andrena are a diverse group that are tricky to identify. They can be distinguished from other small, furry bees by the presence of velvety hairs between their eyes and the middle of their face called “facial fovea”.2
They also carry pollen on their hind legs and on hairs between their abdomen and thorax, which distinguish them from bees in the Megachilidae family.
We hope this little guide will help you experience the native bees in your landscape this spring that make the pollen go round.
Thank you for joining us on this exploration of Oregon’s spring bees and what they are currently doing! We will release two more blog posts in this series, one for each of the four seasons. Blogs will be posted during their prospective seasons, so be sure to subscribe so you don’t miss the next in the series!
Welcome to the Garden Ecology Lab’s “What are the bees doing” mini-series! This series will extend through the four seasons to shed some light on where bees are in their life cycle and what they may be doing during each of the four seasons. We begin with winter, and an overview of the overwintering and nesting strategies of common groups of bees in the Pacific Northwest.
Graphic by Jen Hayes
As the seasons change, where do all the bees go? Different groups of bees utilize unique strategies to survive the cold of winter. In many cases, bees require cold temperatures to develop properly, and as spring rolls around, they rely on thermal cues to determine when to start their next phase of life.
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We can divide bees into four broad categories based on their strategy to nest and survive the winter. There are the Ground Nesters – who find or dig in the ground to nest and lay eggs, Cavity Nesters – who nest in hollow reeds, canes, or in people’s backyard “bee hotels”, Bumblebees – whose new-born queens burrow into leaf litter, waiting to start a colony in spring…. and then there is the oddball: the European Honey Bees, who are not native to North America, but were brought here along with European colonizers and are now key players in modern agriculture. They do things pretty differently than our native bees, so we’ll start our discussion with them.
The European Honey Bee
European honey bees (Apis mellifera) survive the winter huddling in their hive! They are an example of a social insect and many consider a honey bee hive a superorganism. Fueled by their honey stores, the colony huddles together in a mass to thermoregulate at temperatures between 33 – 36°C (91.4 – 96.8°F).1 I love these words from the American Bee Journal:
"The honey bee is a cold blooded insect; but the honey bee colony is a warm blooded creature."1
We will see that honey bees are the only bee in our landscape to overwinter socially. The rest go it alone.
Bumblebees
A Bombus californicus queen on Comfrey (Symphytum sp.) in early Spring. Photo by Mallory Mead.
Bumblebees are social bees too, living in natural cavities most often in the ground, but in winter, the members of the colony die off except for the new-born queens. These queens will fly out of the hive on her maiden voyage to mate with a male bumblebee before finding a place to settle and overwinter alone.
Queens find a safe environment often a few inches deep under leaf litter or light soil. As temperatures decrease in Fall and early Winter, the queens do not thermoregulate. Instead, they enter diapause, which is a state of arrested development. An overwintering queen appears frozen in the soil until warmer temperatures wake her again. In the late Winter or Spring she will begin looking for a site to start her own colony.
Cavity Nesting Bees
About 30% of native bees are cavity nesters who build their nests inside cavities in wood or reeds.2 These bees avoid overwintering as adults, and instead, they lay their eggs in cavities and die before the winter temperatures come.
Female cavity nesting bees forage for pollen and nectar and nesting materials in the spring or summer and make balls of pollen and nectar (often called “bee bread”) as food for their offspring!
They lay eggs on the pollen balls, and then proceed to seal off compartments, one for each of the eggs, until the cavity nest is full. These eggs will hatch into larvae that consume the bee bread as winter approaches.
Bee nests in bamboo sticks, indicated by the mud caps at the front of the stakes. Photo by Gail Langellotto
Video by Oliva Honigman.
Here is a video of a small carpenter bee larva eating its bee bread, magnified under a microscope!
Once the larvae finish off their food store, they may spin themselves a cocoon in which they further develop into pupae. Cavity nesters spend the winter developing from pupae to young adults in their cocoons. These developing bees go into a state called torpor to survive the winter, where the bee is inactive and its body temperature drops, but it still goes through critical physiological processes and development.
These bees must experience low Winter temperatures natural to their region to undergo proper development. Mason bees, for example, have lower survival and vital rates when exposed to warm nest temperatures that simulate predicted climate change temperatures for their region.3
Empty mason bee cocoons that were removed from cavities for an experiment, and a newly emerged male mason bee. Photo by Mallory Mead.
Mason bees (genus: Osmia) are cavity nesters that have become well known in garden and agriculture circles in recent years, but many other groups of bees fall into this category too including leafcutter bees (family: Megachilidae), small carpenter bees (genus: Ceratina), large carpenter bees (Genus: Xylocopa),and masked bees (family: Colletidae).
A friend of the lab, Olivia Honigman, conducted a brief research project on small carpenter bees in Vermont. Here are some photos from her study that showcase a tiny cavity nesting bee, from the genus Ceratina, nesting in raspberry canes.
Ceratina larva in a raspberry cane. Photo by Olivia Honigman.
Ceratina larva and pollen ball under a scope. Photo by Olivia Honigman
Developing Ceratina pupae. Photo by Olivia Honigman.
Ceratina sp. flying into raspberry cane nest. Photo by Olivia Honigman.
Ground Nesting Bees
Last but certainly not least are the ground-nesting bees which make up about 70% of native bee species! Bees from the genera Andrena, Lasioglossum, and Halictus fall into this category.4 Ground-nesters have unassuming nests that are hard to spot, but under the soil, they are putting down bee loaves and laying eggs in a compartmentalized fashion, just like cavity-nesters!
Similarly, adult ground-nesters die after they finish provisioning their nests for their offspring. In the winter, the young bees of the new generation are developing from pupae into adults in their underground nests.
Left: exposed soil revealing tiny holes- could these be bee nests? Top right: A ground-nesting bee pokes its head out of its home. Bottom right: The entrance to a ground-nesting bee’s home.Photos by Gail Langellotto.
Although their nests are modest, some of Oregon’s showstopper bees fall in the ground-nesting category, such as the metallic green sweat bees (Agapostemon).
Metallic green sweat bee on a Clarkia flower. Photo by Mallory Mead.
Long-horned bees from the genera Melisoddes and Eucera also flaunt unique forms with noticeably fluffy, feathery hair on their legs they use for collecting massive volumes of pollen!
A female long-horned bee with dense hairs or scopa on her hind legs. Photo by Mallory Mead
This long-horned bee has “pollen pants” Photo by Mallory Mead.
To invite these bees to your garden, leave patches of earth free from wood mulch and instead mulch with compost! To avoid disturbing ground nests, avoid tilling when possible.4
Something remarkable about nesting in the ground is that, depending on nesting depth, ground nesters are more buffered from extreme temperatures than honey bees and cavity nesters whose homes may be in the direct sun. This may be a critical difference when it comes to surviving climate change.
Changing Climatic Norms…
With climate change upon us, native bees have experienced warmer than usual winter temperatures. These conditions may be suboptimal for their development and survival and encourage bees to emerge earlier in the season. Cavity and ground nesting bees require low temperatures with which they have evolved to reach physiological benchmarks for their development, and scientists worry that there will be phenological mismatches between plants and their pollinators in which bees emerge at different times than when their optimal food sources are in bloom as plants and insects will experience novel timing of thermal queues under climate change predictions.5
As bees and other pollinators face a multitude of challenges, we should support our local bees and appreciate them while we can!
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Thank you for joining us on this exploration of what bees are doing during the winter! We will release three more blog posts in this series, one for each of the four seasons. Blogs will be posted during their prospective seasons, so be sure to subscribe so you don’t miss the next in the series!
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.
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 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
Sweat bee traversing stamen. Photo by Jen Hayes
The underside of a sweat bee with pollen on its abdomen and hind legs. Photo by Jen Hayes
Photo by iNaturalist user baileylemkau CC Some rights reserved.
Jen’s California poppy research plot. Photo by Jen Hayes
Tune in next week for the next edition of our Pollinator Plant PR Campaign.
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.
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 surprising resource: petal clippings! Using their mandibles, the bees cut out 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 petal 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.
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.
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
Cascade Canada Goldenrod
Western Canada Goldenrod
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
Photo by iNaturalist User craigmartin
Photo by iNaturalist User matthias55
Photo by iNaturalist User crwrcwamt
Photo by iNaturalist User suzannehale
Photo by Signe Danler
Photo by Signe Danler
Photo by Signe Danler
Photo by Signe Danler
Photo by Signe Danler
Tune in next week for the next edition of our Pollinator Plant PR Campaign.
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 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
Photo by Patrick Perish
Photo by Patrick Perish
Photo by Jen Hayes
Photo by Patrick Perish
Photo by Patrick Perish
Photo by Patrick Perish
Photo by Patrick Perish
Tune in next week for the next edition of our Pollinator Plant PR Campaign.
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 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
Photo by Mallory Mead
Photo by Jen Hayes
Photo by Jen Hayes
Photo by Jen Hayes
Photo by Jay Stiller-Freeman
Tune in next week for the next edition of our Pollinator Plant PR Campaign.
