Hedgerows, flowering strips, and natural areas that are adjacent to agricultural land have been shown to benefit crop production, via the provision of insect pollinators that pollinate crops. However, we do not yet know the extent to which bee habitat in the form of urban gardens might contribute to pollination services in surrounding crops. We explored whether gardens might provision pollinators to adjacent agricultural areas by sampling bees from gardens in the Portland, Oregon metropolitan area, and estimating typical foraging distances in the context of commercialand residential-scale pollination-dependent crops up to 1000 m from garden study sites. We estimate that garden bees could forage outside of the garden in which they were collected, and that when pollination-dependent crops (commercial-scale or residential-scale) are nearby, 30-50% of the garden bee community could potentially provide pollination services to adjacent crops, if urban bees readily cross boundaries and forage among habitat types. Urban gardens might thus be well-positioned to provision neighboring farms and food gardens with pollination services, or could serve as a refuge for pollinators when forage is scarce or crop management practices are inhospitable. The actual capacity of gardens to serve as a refuge for pollinators from agricultural fields depends upon the extent to which bees forage across habitat types. However, relatively little is known about the degree to which bees move among habitat patches in heterogeneous landscapes. We thus propose a research agenda that can document the extent to which gardens contribute to pollinator health and pollination services at the interface of urban, peri-urban, and rural landscapes. In particular, more data is needed on how landscape context impedes or promotes garden bee movement between habitat types.

Plantings of native flowers are often installed to increase the pollinator habitat in urban and suburban gardens. However, in many regions, it is not known which native plants are best used for pollinator plantings in gardens. Candidate plants must be attractive to pollinators, but they also must have attributes that gardeners find appealing. To identify native plants that are attractive to gardeners, we disseminated two surveys. The first asked gardeners to use a 5-point Likert scale to rate how likely they would be to garden with 23 flowering plants native to the Pacific Northwest United States. The second survey asked gardeners to use a 5-point Likert scale to rate how likely they would be to garden with a subset of 11 of these 23 native plants before and after receiving information about each flower’s attractiveness to bees (Anthophila). Using the first survey, we found a high level of acceptance of native plants by home gardeners (6 of 23 flowers had a mean “likelihood of planting” score of ≥ 4). Additionally, gardeners stated their likelihood of planting these native species increased significantly after receiving information about the bees associated with each plant. Across both surveys, gardeners who identified as “native plant gardeners” stated they would be significantly more likely to garden with all native plant species. Both surveys included an opportunity to share open-ended comments, which revealed that gardeners were most concerned with flower aesthetics and the aggressiveness of growth. Gardeners felt most positively about flower aesthetics and beneficial ecological traits. Many gardeners also commented that they needed more information or were unfamiliar with the plants. This study shows that native plants can have high baseline appeal to home gardeners. Specifically, we identified five native plant species that northwestern U.S. nurseries might consider growing and marketing as pollinator plants because of their high level of attractiveness to bees and home gardeners: globe gilia (Gilia capitata), california poppy (Eschscholzia californica), douglas aster (Symphyotrichum subspicatum), oregon sunshine (Eriophyllum lanatum), and common yarrow (Achillea millefolium).