Pollinator landscapes involve more than just pollinator friendly plants; they are the creation of habitats that support and protect pollinators by providing food, water, nesting areas, and shelter. Creating and maintaining a pollinator habitat incorporates design, cultural practices, pest management, and weed management. Becoming familiar with local pollinators will help in establishing appropriate habitats and choosing plant material.
Habitat needs vary among pollinators. Areas of bare ground or sand are needed for ground nesting bees – which is around 70% of native bees. Bare patches or sparsely vegetated areas don’t need to be large, but should be well drained and in a sunny location. Hollow stems, bamboo, or reeds grouped together are good for cavity nesting bees. Maintained landscapes many times lack appropriate nesting sites, so man-made options can be needed. Bee nesting blocks and logs or stumps that already have beetle tunnels can also be good habitats for cavity nesting bees. When placing stems or logs in the landscape or providing man-made habitats, location is important, with wind protection and sun exposure both important considerations. Hummingbirds need perches and nests on tall trees and shrubs away from predators. Nesting materials are also needed and can include twigs, plant fibers, spider silk, lichens, and leaves. Butterflies need perches for sunning, puddles, and forage plants for caterpillars. Asclepias spp. (milkweed) are important caterpillar forage plants.
A diversity of plant material and floral features is important for attracting different pollinators and having pollinators throughout the year. Planting in clumps and repeating plants throughout the landscape will help avoid having pollinator habitats that are too small or isolated. Clean water sources are important for many pollinators and can be provided by birdbaths, fountains, small ponds, puddles, or a damp salt lick. Different pollinators will have different water requirements.
Having foraging and nesting sites in close proximity can assist in protecting habitats. Limiting mowing to every other week or setting aside areas that can be mowed less, as well as limiting pesticide applications, can help reduce pollinator stress. Pollinator habitats also need consideration during garden clean-up as fallen branches, stumps, and leaf debris can be pollinator habitats or overwintering sites.
Integrated Pest Management (IPM) involves identifying and monitoring pests with the goal of only applying pesticides when pests reach critical levels, and is good practice for limiting pollinator exposure to pesticides. When pesticides are necessary, the least toxic choice possible should be used. Most pesticide labels will provide warnings regarding use around pollinators and toxicity levels. Pesticides should be applied when pollinators are least active (such as late evening) and should be avoided on plants and weeds around blooming plants being visited by pollinators. Use pesticides that do not persist on vegetation, and do not spray at low temperatures when dew formation can re-wet pesticides. Avoid drift by applying on calm days. Most pollinator poisoning occurs when pesticides are applied to blooming plants, but it can also occur from drift, contamination, or residues. Natural pest control through the use of beneficial insects should be used whenever possible.
Mechanical or manual weed control methods such as mowing, cutting, pulling, girdling, and tilling should be used. Perennial groundcovers, weed barriers, hardscapes, and mulch can be used as preventative methods to control weeds. Over-fertilization and irrigation should be avoided as they can result in excessive weeds. Weed pressure can be reduced through proper management of soil nutrition and irrigation. Reintroducing natives and establishing desirable, stable plants can help to resist invasive species. Biological control, or natural enemies, can be used to keep invasive plants manageable when allowed to become established in pollinator landscapes. Biological controls are used to manage unwanted plants through destruction or competition, and are best used when pest populations are low. If physical means prove ineffective, focused selective herbicides should be used.
References:
Pesticide Task Force of the NAPPC - Protecting Pollinators: Why and how pesticide applicators can help them. http://pesticidestewardship.org/PollinatorProtection/Documents/NAPPC.pesticide.broch.Applicators17.pdf
USDA Forest Service - Pollinators. https://www.fs.fed.us/wildflowers/pollinators/animals/
US Fish and Wildlife Service - Attracting Pollinators to Your Garden http://www.fws.gov/pollinator/pdfs/PollinatorBookletFinalrevWeb.pdf
Audubon Society - Hummingbird Friendly Yards. http://www.audubon.org/content/how-create-hummingbird-friendly-yard
University of Maine - How To Create a Bee-Friendly Landscape