- Author: Kathy Keatley Garvey
These are the plants they established in a garden on the grounds of the Harry H. Laidlaw Jr. Honey Bee Research Facility at UC Davis.
"The overall aim of our study was to identify California native plants, and more generally plant traits, suitable for coordinated habitat management of arthropod pollinators, herbivores, and natural enemies and promote integrated ecosystem services in agricultural landscapes," they wrote. "More specifically we ask (a) which native plants among our candidate set attract the highest abundances of wild bees, honeybees, herbivores, predators, and parasitic wasps, (b) if the total abundances of arthropods within these functional groups across plant species are related to the peak flowering week, floral area, or flower type of the focal plant species, and (c) if the total abundances of arthropods within these functional groups are correlated to each other across plant species." (See the results of their research.)
How did they select the plants? "Selected species were forbs that were drought-tolerant, native to California (one exception), and as a group, covered a range of flowering periods throughout the season," they wrote. The one exception: Fagopyrum esculentum, or "domestic buckwheat." Although it's a non-native, it was introduced elsewhere but naturalized in the wild.
Their selections were also based on several other factors:
- indications that they could be attractive to bees based on being listed as nectar and pollen plants for honeybees (Vansell, 1941)
- being recommended as pollinator plants (Xerces Society, 2018)
- being listed as associated with bees in Calflora (2017) or based on earlier collected data on bee attractiveness (Williams et al., 2015).
A further criterion that restricted selection was that "plant material needed for propagation be commercially available either as seeds or plug plants." The exception: Antirrhinum cornutum, commonly known as spurred snapdragon, for which seed was hand-collected.
They excluded plants that are major weeds of crops or pastures. They did note, however, that Amsinckia intermedia (Eastwood's fiddleneck) and Calandrinia menziesii (red maids) can be desirable components of wildlands, but become minor weeds in certain situations (UC IPM, 2018).
And now for the 43 plants, as listed in their chart. We alphabetized them and linked them to the Calflora.org site so you can see images of the plants and the common names. Calflora is a self-described nonprofit organization "where you can learn about plants that grow wild in California (both native plants and weeds)."
- Achillea millefolium, common yarrow
- Amsinckia intermedia, Eastwood's fiddleneck
- Antirrhinum cornutum, spurred snapdragon
- Asclepias eriocarpa, Indian milkweed
- Asclepias fascicularis, narrow leaf milkweed
- Calandrinia menziesii, red maids
- Camissoniopsis cheiranthifolia, beach evening-primrose
- Clarkia purpurea, purple clarkia
- Clarkia unguiculata, Woodland clarkia
- Clarkia williamsonii, Fort Miller clarkia
- Collinsia heterophylla, Purple Chinese houses
- Eriophyllum lanatum, common woolly sunflower
- Eschscholzia californica, California poppy
- Fagopyrum esculentum, domestic buckwheat (non-native, introduced elsewhere but naturalized in the wild)
- Lasthenia fremontii, Fremont's goldfields
- Lasthenia glabrata, yellow-rayed goldfields
- Limnanthes alba, white meadowfoam
- Lupinus microcarpus var. densiflorus, chick lupine
- Lupinus succulentus, Arroyo lupine
- Monardella villosa, coyote mint
- Nemophila maculata, five spot
- Nemophila menziesii, baby blue eyes
- Phacelia californica, rock phacelia
- Phacelia campanularia ,desert bells
- Phacelia ciliata, Great valley phacelia
- Phacelia tanacetifolia, tansy leafed phacelia
- Salvia columbariae, chia sage
- Scrophularia californica, California bee plant
- Sphaeralcea ambigua, desert mallow
- Trifolium fucatum, bull clover
- Trifolium gracilentum, pin point clover
- Eriogonum fasciculatum, California buckwheat
- Gilia capitata, blue field gilia
- Grindelia camporum, gum plant or gumweed
- Helianthus annuus, hairy leaved sunflower
- Lupinus formosus, Western lupine
- Malacothrix saxatilis, cliff aster
- Oenothera elata, evening primrose
- Helianthus bolande, Bolander's sunflower
- Helianthus californicus, California sunflower
- Madia elegans,common madia
- Trichostema lanceolatum, vinegarweed
- Heterotheca grandiflora, telegraph weed
When you're thinking of what native California plants to establish in your pollinator garden, this is a great list, thanks to the Williams lab and their collaborators.
And, if you want to learn more about their research, contact lead author Ola Lundin, a former postdoctoral fellow in the Williams lab and now a postdoctoral fellow in the Department of Ecology, Swedish University of Agricultural Sciences, Uppsala. He can be reached at Ola.Lundin@slu.se.
- Author: Kathy Keatley Garvey
What native California plants are best for attracting pollinators?
Now for answers.
Three pollination ecologists from the University of California, Davis, have just published their research, “Identifying Native Plants for Coordinated Habitat Management of Arthropod Pollinators, Herbivores and Natural Enemies,” in the Journal of Applied Ecology. It details what plants proved most attractive to honey bees, wild bees and other pollinators, as well as what drew such natural enemies as predators and parasitic wasps.
“I hope this study can inform selection of plants that support pollinators and natural enemies without enhancing potential pests,” said lead researcher and first author Ola Lundin, a former postdoctoral fellow in the Neal Williams lab, UC Davis Department of Entomology and Nematology and now a postdoctoral fellow in the Department of Ecology, Swedish University of Agricultural Sciences, Uppsala.
He and co-authors Williams, professor of entomology and a Chancellor's Fellow at UC Davis; and project specialist Kimiora Ward of the Williams lab conceived the ideas and developed the methodology for the research project.
“Planting wildflowers is a key strategy promoted nationally to support wild and managed bees,” said Williams. “Successful adoption of these plantings in agricultural landscapes will require that they not only support pollinators but that they also avoid supporting too many pests. Plant selection going forward will need to balance multiple goals of pollinators pest management and other functions. This research is a first step on the path to identifying plants that will meet these goals."
The trio established 43 plant species in a garden experiment on the grounds of the Harry H. Laidlaw Jr. Honey Bee Research Facility at UC Davis. They selected plant species that were drought-tolerant; native to California (except for buckwheat, Fagopyrum esculentum, known to attract natural enemies and widely used in conservation biological control); and, as a group, covered a range of flowering periods throughout the season.
“For early season bloom, Great Valley phacelia (Phacelia ciliata) was a real winner in terms of being attractive for both wild bees and honey bees,” Lundin said. “Elegant Clarkia (Clarkia unguiculata) flowers in late spring and was the clearly most attractive plant for honey bees across the dataset. The related Fort Miller Clarkia (C. williamsonii) was also quite attractive for honey bees and had the added benefit that a lot of minute pirate bugs visited the flowers.”
Lundin said that common yarrow (Achillea millefolium) “attracted “attracted the highest numbers of parasitic wasps but also many herbivores, including Lygus bugs.”
“In general a lot of parasitic wasps were found on Asteraceae species (the daisy family) and this was a somewhat surprising result considering that they have narrow corollas, and for parasitic wasps relatively deep corollas that can restrict their direct access to nectar. Under the very dry conditions in late summer, Great Valley gumplant (Grindelia camporum) and Vinegarweed (Trichostema lanceolatum) both performed well and attracted high numbers of wild bees.”
The team found that across plant species, herbivore, predator and parasitic wasp abundances were “positively correlated,” and “honey bee abundance correlated negatively to herbivore abundance.”
The take-home message is that “if you're a gardener or other type of land manager, what you'd likely prefer would be a mix of some of the most promising plant species taking into account their individual attractiveness for these arthropod groups, plus several more factors including costs for seed when planting larger areas,” Lundin said.
“Plant choice can also depend on how you weigh the importance of each arthropod group and whether you are interested in spring, summer or season-long bloom,” Lundin added. Those are some of the questions that the Williams lab plans to explore in future projects.
Williams praised the “uniquely capable team that came together.”
“Ola is an emerging leader in considering integrated management of pests and pollinators and Kimiora is a known expert in developing regionally-relevant plant materials to support pollinators,” Williams said. “They and some talented UC Davis undergraduates--notably Katherine Borchardt and Anna Britzman--compiled a tremendously useful study.”
The overall aim of the study “was to identify California native plants, and more generally plant traits, suitable for coordinated habitat management of arthropod pollinators, herbivores and natural enemies and promote integrated ecosystem services in agricultural landscapes,” the researchers wrote.
More specifically, they asked:
- Which native plants among our candidate set attract the highest abundances of wild bees, honeybees, herbivores, predators, and parasitic wasps,
- If the total abundances of arthropods within these functional groups across plant speacies are related to the peak flowering week, floral area, or flower type of the focal plant species, and
- If the total abundances of arthropods within these functional groups are correlated to each other across plant species.
“A first critical step for design and implementation of multifunctional plantings that promote beneficial arthropods while controlling insect pests is to identify suitable plant species to use,” the authors wrote in their abstract. “We aimed to identify California native plants and, more generally, plant traits suitable for the coordinated management of pollinators (wild bees and honey bees), insect herbivores and arthropod natural enemies (predators and parasitic wasps).”
At the time, the Laidlaw grounds included nearly 50 bee colonies: some 20 to 40 honey bee colonies, and eight managed research colonies of the yellow-faced bumble bee, Bombus vosnesenkii.
The project drew funding from the USDA Resources Conservation Service, USDA Agricultural Marketing Service, USDA National Institute of Food and Agriculture and a Swedish foundation for scientific research, the Carl Tryggers Stiftelse for Vetenskaplig Forskning.
(Note: An upcoming Bug Squad blog will list the 43 plants the researchers used.)