Habitat Gardening
Eastern Kingfisher by Holly Elderbusch
Plant a Native Habitat Garden to Welcome Life to Your Yard!
In a world of climate change and environmental destruction, it has become vital for anyone with a garden, a yard, or even a sunny porch to contribute to the survival of other species by providing not just berries for birds and nectar for butterflies, but support for the whole life cycles of those animals and others we seldom think about—native bees, caterpillars, moths, and even the humble insects that live in the soil. We must think about gardening in a new way, with new goals and new aesthetics, and with new rewards.
We can start by using plants that are native to our area of the country, and especially to our ecosystem, which here in the Hudson Valley is defined as the Eastern Broadleaf Forest, Oceanic Province: deciduous forests were here before us, with a specific palette of plants that developed for this seasonal cycle of sun and shade within the forests, with a specific pattern of bloom time for food plants and shelter needs for foraging, reproducing, and migrating animals.[i] There can be ecological value in plants that are native elsewhere, but there is simply more value in plants that evolved together with the animals and insects that live here. 30% of our native bees, for example, are so entwined with specific plants that they use only a certain species—if that plant is not present, neither are they. Many bees are more generalist, but they have very short lifetimes, usually only a few weeks to mate, make a nest, lay eggs, and collect pollen for them. Those lifetimes are synchronized with bloom times for our native plants, not necessarily with those of exotics.
Native plants are eaten by native insects. Native butterflies lay their eggs on their leaves that hatch into caterpillars that are eaten by native birds: studies have shown that chickadees need 6,000 caterpillars to feed a single clutch of eggs. Those caterpillars are usually specific to particular host plants, and those host plants evolved in tandem with them. Again, if there are not enough host plants for caterpillars, there are not enough caterpillars for birds: biologists have found that areas with less than 70% native plants cannot support the reproductive cycle of the Carolina chickadee.[ii]
This gives us one of our goals in habitat gardening: at least 70% of our gardens should be planted with natives. (This, admittedly, can be hard to gauge, but I figure it gives a little leeway to plant a few of one’s favorite non-natives in a garden otherwise devoted to natives.) And some native plants are especially valuable. Oaks, cherries, birches, dogwoods, and willows; goldenrod, strawberry, sunflower, joe-pye weed, and aster—these are some of the best plants in terms of hosting the greatest number of butterflies and moths in our area.[iii] Doug Tallamy calls them “keystone plants,” because they are so fundamental to supporting ecosystems.[iv] “A landscape without keystone genera will support 70 to 75 percent fewer caterpillar species than a landscape with keystone genera, even though the keystone-less landscape may contain 95 percent of the native plant genera in the area,” Tallamy says, citing a study by Desiree Narango.[v] But there are other considerations than hosting butterflies and moths, as important as that is, and that brings us back to habitat.
Animals, like us, need food, shelter, and water, and habitat gardening needs to provide all those. Some plants offer food in insect form, some in pollen or nectar, some in seed or berry or leaf. Some plants offer excellent nesting sites for birds, some provide shelter in bad weather. Dead plants—leaves, snags, wood piles, logs—are vital to many species, for shelter, nesting, and food. But many, if not most, animals use more than one plant, and more than one environment, at different times in their life cycles. Oaks host lots of caterpillars, but most caterpillars crawl off their host plant before molting to their pupal stage, and most of them do so by falling to the ground and spinning cocoons or burrowing into the soil. If they drop onto lawn, there’s no leaf litter or loose soil for them to use. Bees collect pollen and drink nectar, but some use plants for nesting. Many skippers (a kind of butterfly) hibernate and lay eggs in the bases of grasses, but nectar on flowers like asters and thistles. Birds may eat insects, seeds, or even buds, from different plants, and nest in still others. So use keystone plants as the backbone of your garden, but offer diversity as well, and plant and maintain them so animals can use them.
[i] https://www.pollinator.org/PDFs/EasternBroadleaf.Oceanic.rx18.pdf
[ii] https://www.pnas.org/content/115/45/11549
[iii] http://www.nwf.org/NativePlantFinder
[iv] Douglas Tallamy, Nature’s Best Hope: A New Approach to Conservation that Starts in Your Yard (Portland: Timber P, 2020), 139.
[v] Ibid., 141.
What Can You Do?
First, don’t be overwhelmed! Transitioning to Habitat Gardening takes time. The first thing you can do is start adding native plants that are beneficial to birds, insects and other wildlife. We’ve compiled a vast list of Plants for Habitat Gardening including trees (large + small), shrubs, perennials + grasses, and vines that you access by CLICKING HERE.
In addition to adding native plants, there are five other things you can start doing today; with time, you will be amazed at the life you can bring into your yard!
REDUCE LAWN
This is one of the most important things suburban gardeners can do. Lawns are made up of non-native plants, and they offer almost no ecological value, and what’s more, they require lots of resources of fertilizer, water, and time. They produce air and water pollution from fertilizer, pesticides, and emissions from mowing and blowing. Lawn does have some function, as playground and walking surface, but we simply don’t need acres and acres of it. We need to change our expectations, our Victorian-era aesthetic that considered lawn an indicator of wealth, and instead use grass sparingly.
Lawn should be a rug, not a carpet. Expand your plantings, think of gardening less in horizontal than in vertical terms: plant in layers, from ground-hugging plants to taller plants and grasses, to shrubs, to understory trees, to canopy trees. Imagine your house as the center of a forest clearing, with meadow around it, rising to edge plants and trees. Lawn should be just the jumping-off point, the bland background to the exciting diversity of life and color that is your habitat garden. For the lawn that remains, if any does, you can also eliminate the need to fertilize, at all, by introducing white clover, which is not native, but which is both beneficial for pollinators and nitrogen-fixing, so it takes fertilizer right out of the air and makes it available for the lawn grasses next to it. Studies have shown that if a nitrogen-fixing legume, like clover, makes up about 30% of a grassy area, it supplies most of the nitrogen the grass needs. So no fertilizer, no fertilizer salts to stay in the ground and kill your fireflies, and no fertilizer runoff to feed algae blooms in our waterways. And the flowers are a food source for a whole variety of pollinators: 12 bees and ten other species of pollinators.
Mow less often, no lower than 3½ inches, and mulch the clippings into the lawn. Irrigate only when you absolutely have to, and don’t use pesticides!
EMBRACE UNTIDINESS
Despite all the magazine articles, your garden is not an extension of your house. You don’t need to clean it: in many ways, a habitat garden is self-maintaining. Leave your leaves, as much as you can, where they fall under trees and into flowerbeds and shrubberies. When you must rake them, tuck them into piles in the far corners of your garden, to incorporate later into your compost pile or simply to allow to decompose into mulch that you can spread in your garden beds.
Forests have leaf litter, dead logs and piles of sticks, all the fertile regeneration that goes with decomposition. A fallen tree becomes food for fungi and insects. As the tree decomposes, nutrients are recycled into the soil, while innumerable insects become, in turn, food for birds and other animals. It’s one of the most productive habitats there is, so don’t tidy away your dead wood. Make and leave piles of sticks, for refuge for birds, animals, and even bees, some of which nest in them. Leave standing dead trees, if you can safely do so, for use by cavity nesters. The most notable group of wood users in snags are the primary cavity nesters, wood-peckers and nuthatches that excavate nest cavities in the decayed wood of standing trees. When they leave, other birds and mammals are waiting in line as tenants. These structures are used for foraging, nesting, denning, roosting, and resting, often serving multiple squatters simultaneously.
USE LIVE PLANTS + LEAVES INSTEAD OF MULCH UNDER TREES + SHRUBS
Wood chips work—they suppress weeds—but they do very little for wildlife. Butterflies can’t overwinter in them, as they can in leaves. Birds can’t rootle around in them, looking for bugs, because there aren’t many bugs there. Bees can’t nest in them (70% of native bee species nest in the ground, spending 11 months of the year there). Leave some dirt bare, especially on south-facing slopes.
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LEAVE YOUR GARDEN MESSY IN THE FALL
Many scores of beneficial insects, like ladybugs and predatory wasps, as well as native bees, butterfly chrysalises, eggs, and even butterflies themselves, overwinter in leaves on the ground, on perennial stems and in perennial plant crowns, and tidying away all that plant material will kill them or leave them with nowhere to shelter. Wait well into spring to remove them—until temperatures average in the 50s—and even then cut the perennial stems of wild bergamot, asters, goldenrods, yellow coneflower, echinacea, and tall coreopsis back to 12-18” rather than to the ground, since their hollow stems can provide nesting sites for bees.
PROVIDE A WATER SOURCE
Anything from a birdbath to a waterfall to a pond can be used to attract birds and other wildlife. The sound of water in itself attracts birds. People like it, too. If you have or put in a pond, make sure there is a slope for birds to gain access to the water, preferably a flat area of pebbles just at the surface edge for insects, and sufficient aeration. If it is deep enough to accommodate fish, the ecological balance will be enriched, as well. Celebrate any wetland you have, by planting water-loving plants that will attract other species of pollinators, butterflies, and birds than those of different habitats.