Garden Variety: Attract bats to the yard and garden for pest control
If you have ever seen bats swooping after mosquitoes at dusk on a summer evening, you know they are voracious when it comes to reducing the insect population. In fact, a single little brown bat can eat up to one thousand mosquitoes in an hour. Many gardeners (and people who simply enjoy being in the yard in the evening) are starting to recognize the benefits of bats and take an interest in attracting the animals to their yards.
Attracting bats is a little more complicated than simply installing a bat house. This is a case where you can build it, but they might never come. Shelter is important, but so are water and food. And, since mosquitoes and other insects are plentiful in Kansas, bats are unlikely to be out searching for food too far from home.
If you are ready to try to get bats to move in to your yard, start with providing food and water. If there is a stream or some other natural water source nearby, that may suffice. Otherwise, consider installing a landscape pond, a birdbath, or a small fountain.
For bat food, bat experts recommend planting flowers to attract insects that bats like to eat (besides mosquitoes). Night-blooming flowers such as evening primrose are a good example. Plants with very fragrant flowers also provide a lure to insects. For the Midwest, the Organization for Bat Conservation recommends monarda, sedge, penstemon, stiff goldenrod, coneflower, phlox, Virginia mountain mint, aster, New Jersey tea, and Joe Pye weed in addition to evening primrose.
Other plants that may be helpful for luring insects that bats like to eat are dahlia, marigold, nicotiana, thyme, and native honeysuckles. For best results, use a variety of species that bloom across the season.
Once food and water are established, consider how you want to provide shelter for bats. In the wild, bats roost in trees or caves. If you happen to have an ideal bat habitat already, you are set. For the rest of us, especially those with small urban or suburban yards, a bat house is probably the best option. You can build a house yourself from plans available through many sources online, or buy a commercially produced bat house.
Bat houses should be mounted on the side of a building or on a pole. This provides the best protection from predators. Mount houses high – most sources say 15 feet or more off the ground to allow the bats to drop out and catch flight. Bat house(s) should be small and tight to prevent rain, drafts, and predators from entry.
Finally, examine your own house and make sure any gaps or holes where bats could enter are sealed. Do this before mid- to late-March when bats will be coming out of hibernation. Some species can enter a hole as small as three-eighths of an inch diameter. Bats commonly take up residence in attics, garages, sheds, and buildings when given the opportunity for entry. Although they are good insect-eaters, allowing them to share your home is not ideal. Their excrement has a strong smell, they are noisy, and they can occasionally carry disease.
According to Kansas State University, 15 species of bats are found in Kansas. Some are full-time residents and others migrate through. The little brown bat and big brown bat are the most common. Both hibernate.
— Jennifer Smith is a former horticulture extension agent for K-State Research and Extension and horticulturist for Lawrence Parks and Recreation.