Inviting the Pollinators
Written onJanuary 01 , 2013
Several years ago I was privileged to spend weeks and months at a time working in southern Mexico with organic coffee and cacao farmers. My first visit to a coffee farm is etched in my memory primarily through sound—the sound of bees. As I walked into the forest I saw coffee trees, yes, but also mango, banana, papaya and understory bushes and shrubs whose names I didn’t know. The hum of insects filled my ears. Only then did I look around and see that the trees were vibrating with the buzzing bees: it was flowering time in the coffee zone.
After returning to Vermont and settling onto land that had been a farmstead in centuries past, I heard that sound once again, when bees enveloped the flowering ancient apple trees on my land. Lately the apples aren’t doing so well, and neither are the bees. There are fewer and fewer bees each summer, or so it appears to me, and changing weather patterns seem to be taking a toll on the semi-wild fruit trees that provided some of their sustenance. But my study of coffee and cacao farming in Mexico has convinced me that the strategies farmers there use to keep their fields productive and resilient can be applied to our own gardens and surrounding landscape in New England. A critical component of their strategy is providing habitat for bees and insects that provide pollination and other underappreciated services in pest control and decomposition. These creatures are also food for birds, bats and frogs, which in turn help keep our gardens healthy.
Of course we gardeners and local food enthusiasts want to assist pollinators, since they enable our crops to bear fruit. But, in a larger sense, pollination is also critical to life on our planet. It is pollination, or, to put it another way, plant sex that facilitates genetic mixing and therefore adaptation of plants to diverse climates and geographic conditions. It also allows humans to select and improve crops for specific flavors, textures, disease, and pest resistance, and to better meet our nutritional needs. Unless we believe that all of this can be accomplished through genetic engineering in laboratory conditions, we owe it to ourselves and future generations to do everything we can to enhance habitat for pollinators.
Who are the pollinators? Honeybees, whose decline has been widely chronicled, are only part of the story. According to Stephen Buchmann and Gary Paul Nabhan, authors of The Forgotten Pollinators, there are some 80,000 other species of bees, wasps, and ants; some 20,000 species of butterflies and moths; 15,000 species of flies; 210,000 species of beetles; and thousands of birds, bats and other animals that contribute to pollinating the flowering plants of the world. Here at home, the Vermont Center for EcoStudies lists 21 species of bumblebees on its website, and these important pollinators, like our honeybees, are suffering for a variety of reasons, not all of which are clearly established. Habitat loss is likely a key factor, and evidence is mounting that the use of pesticides on gardens, lawns, and around our homes is also affecting insect health.
So what can be done? Of course we should make sure we have plants flowering from early spring to late fall to provide pollen and nectar. But if we want pollinators to stick around, we need to think not only of their needs during flowering but throughout their life cycles. They need places to meet their mates and reproduce, to bear young and raise them and, for overwintering species, places to settle down for hibernation. With this in mind, think of your garden as an agro-ecosystem, and of the land surrounding your garden as part of that ecosystem. This is where the lessons from the agro-forestry systems of Mexico come into play. There, coffee and cacao are grown among a diversity of other plants, much like the natural forest. In addition, people grow gardens around their homes that include fruit trees and understory plants such as vegetables, medicinal plants, and plants grown for animal fodder or for construction materials. The transition between forest and garden, in some cases, is hardly noticeable. We can do the same in our own yards and gardens using systems sometimes referred to as “forest gardening” or “permaculture.” Short of taking a permaculture design course though, there are many ways that all of us can improve the situation for pollinators in our landscapes.
One book I turn to again and again is Insects and Gardens by Eric Grissell (with incredible photographs by Carll Goodpasture). Grissell, an entomologist and zealous insect advocate, suggests that the key is increasing diversity in plant communities in and around the garden. Think about plant structure: some plants are upright, some are squat, some are trailing. Aim to increase this “architectural diversity” by having some of each size and shape throughout your landscape. Flower shape and size (and a palette of diverse colors) is also important—each plant catering to different pollinator desires.
Think about temporal diversity as well: plants develop and blossom at different times, so at any given time we should try to have plants at various stages of development to meet insect needs at all stages of their development. Interplant vegetables, herbs, and flowers throughout your garden and you will always have pollinators nearby when your vegetables need them. Companion plants like these provide a shelter for insect interactions (mating, eating one another—yes, it happens–laying eggs, etc.). To provide refuge for overwintering insects, plant dwarf conifers and evergreen shrubs around the periphery of your gardens.
It’s not just the plants that create habitat diversity. Insects, including pollinators, also need water—a pond or wet swale or even a bird bath in summer will help meet pollinator needs. Soil diversity is important as well, since different insects need different kinds of soil for nesting. Some bumblebees, for example, like sandy soil, so you might want to reconsider any impulse to create uniform soils in your landscape. And different plants need different soil types, so soil diversity enhances plant diversity and thus creates a more complex insect habitat. Similarly, differences in exposure to sun are important to improve insect habitat so don’t eliminate all your trees in order to have a sunny garden! Insects need shade as well as sun just as we do.
And last, don’t be so neat and tidy! Leave seedheads in the garden well into fall so that insects and birds can continue to forage among the plants. Allow flowering plants such as goldenrod and asters to proliferate around your gardens to provide nectar as long as possible in the fall. Keep most of your soil covered with mulch or messy garden debris, as many insects make their homes there. Many garden gurus advocate keeping your gardens free of debris for just this reason: to avoid providing a refuge for overwintering garden pests, such as vine borers and snails. However, as Eric Grissell points out, the best way to keep your garden free of pests is to make sure predator species (think spiders and ground beetles) also have habitat. Many of these predators, such as the various species of predatory wasps, are also important pollinators. (Do keep a few spots bare though, as some bee species like exposed ground for their nesting sites.)
To benefit our native pollinators, it is important to populate our gardens and landscapes with a wide variety of native plant species, since these have co-evolved with insects over time to meet each other’s needs. This is a great time of year to be thinking about what to plant next spring. Fedco Trees is a good source for a broad assortment of native flowering trees, shrubs, medicinal plants, and herbs. This year’s catalog (ordering deadline: March 8, 2013) includes a list of spring, summer, and fall blooming native plants that can specifically enhance pollination in the home orchard. Spring-blooming plants include wild geranium, wild lupine, and dandelions—not native, but nonetheless valuable to pollinators. (Once again, be less tidy: let those dandelions bloom!) Summer-blooming plants include milkweeds, Joe-Pye weed, and monarda (bee balm). Plants that bloom in the fall include goldenrods and asters. The many species of goldenrod attract a wide range of pollinators; sometimes the humming in the goldenrod near my gardens rivals the sound of those Mexican coffee trees at flowering time!
Other plants attractive to native bees include Amelanchier (serviceberry), Baptisia (false indigo), sunflowers, lavender, black-eyed Susan, brambles of all types, lamb’s ear, comfrey and tansy. Fedco Seeds provides a “beneficial insect mix” of a selection of annual and perennial flowering plants that can be seeded in wide borders around and within gardens providing excellent pollinator habitat. Fedco recommends that plants designed to attract pollinators be planted in large clumps three or four feet in diameter so that pollinators can spot them from a distance.
In addition to planting a wide range of species and enhancing the architectural and structural diversity of one’s garden and surrounding landscape, there’s another critically important thing we need to do to improve the lives of pollinators. Don’t use pesticides! Pesticides of all kinds are designed to kill insects at all stages of their life cyles. Some of these target specific insect pests (some of which are the larvae of important pollinators) and others are broad-ranging in their target species. Even pesticides approved for organic use can be problematic. Spinosad, an “organic” pesticide recommended for numerous garden pests, is highly toxic to bees and butterflies. It is suggested that it not be used when pollinators are likely to be around. But don’t we want pollinators around most of the time?
Here again, thinking of our gardens as part of a larger agro-ecosystem can be the key to not only protecting pollinators, but also to protecting our own health and the health of our food supply over time. By improving habitat for pollinators, we also improve habitat for birds, bats, and predatory insects. Ultimately this proliferation of insect and animal life in our yards and gardens—our own habitat after all—is our best hedge against any damages we may suffer from pests. We must measure the short-term gain of cosmetically perfect broccoli against the benefits of increased productivity and the long-term well-being of the myriad species of pollinators upon whose lives we depend.