How to embrace, support pollinators
Q: I see lots of information online about which flowers best attract bees, but is there anything else besides butterfly host plants that I should be adding to a pollinator garden?
A: In short, it’s a message you may be accustomed to hearing — use a diversity of plants (predominantly native, where possible), restrict pesticide use, and minimize habitat disturbance (like garden “clean-up”). As with all living things, sources of food, water, and shelter will take care of their basic needs.
This coming week is National Pollinator Week, so it’s a great time to evaluate how our gardens are serving pollinators of all kinds. Efforts to boost pollinator support invariably focus on bees and butterflies because they’re the most approachable insects among those that pollinate flowers, but they’re far from the end-all and be-all of pollination services. Pretty colors and cute ‘n’ fuzzy traits certainly help everyone feel more comfortable about the insects interacting with our plants, but there’s a wide, diverse world out there of organisms we can help support and which plants depend on.
People tend to malign wasps, but they are great floral visitors when they’re not hunting other insects. (Adult wasps subsist on a liquid diet for their calories and nourishment; they only use the prey they catch, or picnic meat they pilfer, for feeding their young.) The vast majority of them prefer to ignore us as they go about their busy chores. From species smaller than an ant to those around 2 inches long, they’re going to visit an equally-diverse range of plants. Bees evolved from wasps, and several solitary species use hollow plant stems for nesting, so even plants they’re not interested in for nectar can still serve a pollinator-supporting function.
Flies as a group are often dismissed because some species associate with unpleasant smells or try to bite us, but plenty do not. Even those which do favor carrion, fungus or rotting fruit serve as important pollinators for several of our native plants like pawpaw, wild ginger, and Jack-inthe-pulpit. The bee-mimicking flower flies are aptly named for their pollinating benefits, and the bonus is their larvae hunt aphids and other pests.
Beetles are pollinators for plants like magnolia, Carolina allspice, pawpaw, spicebush and water lilies. Soldier beetle adults, which look a bit like fireflies, are fond of aster-family blooms and their predatory larvae provide great free-range pest-control services for the garden.
Climate change impacts may disrupt pollinator-plant relationships in myriad ways, bringing this mutually beneficial partnership out of sync, with either plants or insects emerging too early in spring, before the other is ready. Temperature and precipitation
irregularities and extremes at any time of year could ground pollinators during key flower fertility windows, render flowers sterile by killing pollen (pollen grains are living plant cells), or damage blooms from late frosts.
By using a genetically-diverse mix of native plants, you increase the odds that not all individuals will be equally vulnerable to the same stresses. Over time, plant species that are native just south of us may wind-up being more aligned with conditions here, but it remains to be seen how our local insects can adapt to these habitat changes and new resources. If we can support healthy populations of pollinators, then hopefully that boost in their own genetic diversity enables them to adapt more quickly and be flexible enough to survive these new challenges.
Q: Do we have native spireas? I’ve learned that the ones I see in landscapes everywhere and available at garden centers are not, though I find them appealing for their leaf colors and long bloom. A:
A few of the non-native spirea species commonly used in landscaping have seeded into natural areas, though none are currently flagged as invasive. But yes, we do have native spireas! I wish they were more widely used, and more widely available. You may need to check with native plant nurseries specifically since gardeners aren’t
as familiar with them compared to more “mainstream” native shrubs like winterberry and summersweet.
While some have different bloom shapes (more of a cone than a flat cluster), they look
pretty similar to each other otherwise.
They don’t have the cultivar palette of varying leaf colors or compact growth habits, but they pair wonderfully with other meadow natives for a variety in bloom colors and plant textures.
Maryland native species include white meadowsweet (spiraea alba), broadleaf meadowsweet (spiraea latifolia), and steeplebush (spiraea tomentosa) and bloom colors are either pink or white, beginning around midsummer and sometimes continuing into early autumn. They host the caterpillars of several species of moths and the blooms attract pollinators.