The Pollinator Buzz – Volume 2, Edition 1, Spring 2025
Welcome to The Pollinator Buzz! In this quarterly newsletter, we will discuss what bees are doing right now, student research, recent pollinator-related discoveries, and beyond!
The Basics
There are nearly 400 bee species recorded in Massachusetts, and the number keeps growing! These bees come in all different colors, shapes, and sizes. Unlike social honey bees and bumble bees, most of the bees in New England are solitary and live in the soil. Because bees exhibit all sorts of different behaviors and traits, there are many conservation approaches that can help preserve biodiversity in this region.
Want more information? Check out our research brief.
A Plant to Observe: Wild Geranium (Geranium maculatum)
An herbaceous perennial, wild geranium is recognizable by its short growth habit and purple petals. Many bees visit the blooms, which are typically at their peak in the late spring, for both pollen and nectar. Beyond generalist foragers, G. maculatum even supports a specialist bee, Andrena distans. This mining bee species limits its pollen foraging to just geranium plants, meaning it relies heavily on the presence of native geraniums to complete its life cycle. Butterflies are also attracted to the nectar-rich blooms, and some native bird species consume the seeds.
Wild geraniums are somewhat adaptable when it comes to growing conditions, though they tend to do best in areas with partial sun exposure and moist soil. This plant may spread over time and is sometimes used as a ground cover. Readily available in many plant nurseries, it can be planted from seed or plugs, though it is known to be slow to germinate and reach maturity.
Straight Species Natives vs. Native Cultivars: Is One Choice Better for Pollinators?
As enthusiasm for pollinator-friendly gardening has increased, so has interest in choosing native plants in the interest of supporting bee populations. With this has come questions and debate regarding the value of native cultivars in pollinator habitat. Before we delve into the research, let’s highlight some important definitions.
A native plant is defined in restoration ecology as a plant growing in a particular region, prior to European settlement. Native plant status is tied to a geographic state, such as native to North America, native to Massachusetts, native to Connecticut River Valley, etc. (e.g., Achillea millefolium).
A straight-species native plant meets all qualifications for a native plant and has not been bred or modified in any way. These plants should look exactly like a plant of the same species growing in the wild (e.g., Achillea millefolium).
A variety is a naturally occurring form of a plant within the species, such as a white- flowered form of a normally pink-flowered plant. These would be labeled with ‘var.’ between the species and variety name (e.g., Cercis canadensis var. alba, a naturally-occurring white-flowered variety of the typically pink-flowered tree).
Cultivars, whether native or not, are a cultivated variety of a plant ("culti"-"var"). Many are developed through plant breeding, but some may be from naturally occurring variations in wild plant populations. Many food crops are cultivars (e.g., the highbush blueberry cultivar Vaccinium corymbosum ‘Bluecrop’).
A native cultivar is a named, cultivated variety of a plant derived from a native plant species. Cultivars may be selected from wild populations or bred for specific plant traits (e.g., Achillea millefolium ‘Balvinviolet’).
Before we dig into research results, it’s important to note that native cultivars vary significantly in their level of cultivation. Some may have been selected as natural variants from a naturally occurring wild population, while others may have been bred so far as to have greatly reduced fertility in the plant. Flower height, petal color, modifications in floral rewards like nectar and pollen, and other factors may all influence pollinator visitation.
Annie White conducted an experiment at the University of Vermont examining 12 native plants and 14 cultivars. Her results indicated that pollinators significantly preferred native plants 58% of the time (White 2016). Another study out of Oregon State University compared 8 straight-species natives and 1-3 of their respective cultivars, finding that native types were preferred about 37% of the time (Hayes et al. 2024). It’s important to note, too, that specialist bees were found more often on native types than cultivars.
A classic New England example in the conversation on native types versus their respective cultivars is the hydrangea. The smooth hydrangea, Hydrangea arborescens, is native to Massachusetts and boasts 99% fertile flowers, compared to just 42% fertile flowers in its ‘Annabelle’ cultivar, bred for showiness (Ricker et al. 2019). Researchers from Connecticut found that 'Annabelle’ had one-third of bumblebee visits, compared to the straight species native.
Sometimes, there is no significant difference in pollinator preference between native types and their cultivars. Annie White’s study found that there was no difference one-third of the time, while Hayes’ study found that there was no difference over half the time. This suggests that cultivars may be ecologically appropriate substitutes for wild-type native plants when it comes to supporting pollinators, but this should be determined on a case-by-case basis (White 2016).
In the select cases where cultivars were preferred, they were closely related to their native type (in petal color, nectar and pollen production, etc.). This supports the idea that cultivars which are selected from wild populations, nursery populations, and otherwise minimally altered from their wild type, are likely the best substitutes for native plants in pollinator plantings (White 2016).
Key take homes:
- Native cultivars are not universally more or less attractive to pollinators, and best practice is to evaluate them on a case-by-case basis (Hayes et al. 2024, White 2016, Ricker et al. 2019)
- Minimally altered native cultivars are the most appropriate substitutes for wild type natives in pollinator plantings (Hayes et al. 2024, White 2016)
Written by UMass Extension Pollinator Specialist Nicole Bell. For questions related to the program, please contact nicolebell[at]umass[dot]edu (nicolebell[at]umass[dot]edu)
Definitions from this blog come from Jen Hayes at the Oregon State University Garden Ecology Lab. To read more about their work and these definitions, visit: For Gardeners | College of Agricultural Sciences
Hayes J., Bell N., Best L., et al. 2025. Pacific Northwest native plants and native cultivars Part I: Pollinator visitation. Environmental Entomology. 54(1):199–214. https://doi.org/10.1093/ee/nvae126.
Ricker, J.G., Lubell, J.D., Brand, M.H., 2019. Comparing Insect Pollinator Visitation for Six Native Shrub Species and Their Cultivars. https://doi.org/10.21273/HORTSCI14375-19
White, A.S., 2016. From nursery to nature: Evaluating native herbaceous flowering plants versus native cultivars for pollinator habitat restoration (Ph.D.). The University of Vermont and State Agricultural College, United States -- Vermont.
UMass Extension’s pollinator program focuses on wild bee and non-bee insect education and outreach for farmers, gardeners, landscapers, and beyond.
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