It may come as a surprise that just a few trees, shrubs, and herbaceous plants feed 90% of moth and butterfly caterpillars that in turn provide important pollination services as well as food for birds and other wildlife. And for many caterpillar species, the choice is a specific “host plant.”

In the Northeast, the tree that tops the list is our native oak, hosting 436 caterpillar species. Cherry, birch, cottonwood, and maple are also high on the list. Similarly, pollen specialist bees rely on flowering perennials and shrubs for specific pollen to feed their young. Collectively, these important native trees, shrubs, and herbaceous plants are considered keystone plants.

Keystone plants are critical to the food web and necessary for many wildlife species to complete their life cycle. Without these plants in our landscapes, butterflies, native bees, and birds could not survive. It is important to note that the vast majority of terrestrial birds require insects for their diet. Baby birds are exclusively fed insects and especially caterpillars because they are soft, nutritious, and easily digested. It is estimated that it takes between 5,000-9,000 caterpillars to feed a single clutch of baby birds.

Because our native trees top the list of keystone species, what is underneath them truly matters. As forests and fields continue to be developed, many pollinators and beneficial insects are displaced and must find new homes. As they retreat to our yards, the native trees they find are typically surrounded by clipped grass or wood mulch, landscaping practices completely inhospitable for many forms of life.

In order to preserve important wildlife, we must rethink our garden practices. Soft landings are plantings under keystone trees that contain a variety of regionally appropriate native plants. With leaf litter and plant debris, these areas provide shelter and habitat for a number of pollinators and beneficial insects such as butterflies and moths, bumble bees, fireflies, lacewings, and beetles.

Many caterpillars and other insects survive our winters by burrowing under leaf litter. Removing leaves from under trees takes away their hiding places and threatens their survival. Leaf blowers are particularly destructive as they blast away this habitat along with important insects. Bagging leaves removes these guys all together. Even relocating leaves can disrupt an insect’s ability to complete its life cycle. That is why it is so important to designate an area(s) in your yard you are going to leave undisturbed as habitat for these important creatures. Take a cue from our forest trees, where leaves are not removed: forest trees thrive because leaf litter and decaying plant material provide valuable nutrients.

We all care about birds and other wildlife, so incorporating soft landing areas is a win-win for both beneficial insects and our landscapes. Areas under trees are often too shaded to effectively grow turf grass anyway, so why not choose to plant around them instead. These understory gardens not only provide “soft landings” for caterpillars and other insects seeking shelter any time of year, they also protect tree roots and bark from injury caused by mowers and string-trimmers; injuries that make trees susceptible to disease and pests.

This area under a tree’s canopy can be planted with plants that prefer shade or partial shade. Many native plants are well-suited to a tree’s understory and are also known as “green mulch.” Plants eliminate the need for wood mulch that is counterproductive to preserving beneficial insects and, when piled high, is detrimental to tree health. Spring ephemerals such as Virginia bluebells, bloodroot, and trillium are perfect soft-landing plants. They emerge from beneath leaf litter and bloom before the trees above leaf out. Above ground parts of these early bloomers eventually fade away to make room for early summer perennials while their underground parts remain viable to emerge again the following spring. There is a plethora of native plants suitable for soft landings, offering continuous bloom from early summer (woodland phlox) right through to fall (asters and goldenrod). For a list of local native plants along with tips for planting soft landings, search “Soft Landings by Heather Holm.”

Soft landings under keystone trees also build healthy soil and sequester more carbon than turf grass. They protect trees and reduce time spent mowing. Creating beautiful garden spaces under keystone trees that provide habitat for pollinators and beneficial insects and food for birds is what soft landings are all about.

My Backyard Habitat is published monthly in cooperation with The Newtown Bee by Protect Our Pollinators. For more information or to reach out, visit propollinators.org.

Creating beautiful garden spaces under keystone trees that provide habitat for pollinators and beneficial insects and food for birds is what soft landings are all about. —Holly Kocet photo