Raise Keystone Plants in Your Homegrown National Park

Douglas Tallamy, a professor of entomology and wildlife ecology at the University of Delaware, champions native “keystone” plant species in his recent books, Bringing Nature Home and Nature’s Best Hope. Keystone plant species support 90 percent of the insects that are the only food available for most nesting birds and their young. Dr. Tallamy highlights plants that nourish priority insects – caterpillars, bees, and sawflies – which are the largest and most numerous, nutritious, and edible.

Because so much of our woods, wetlands, and other wildlife habitats are degraded into small, disconnected patches, Dr. Tallamy sees our backyards and woods as more vital than ever to the survival of native wildlife.

What can you do to make your yard and woods part of what Dr. Tallamy calls the Homegrown National Park?

The first thing to remember is that all of the keystone plant species are native. As non-native (or “exotic”) plants did not evolve with our native insects – and other native animals – wildlife do not often recognize the non-natives as food. Even those plants introduced hundreds of years ago continue to support very few native insects. For example, the reed “phragmites” – now commonly seen overtaking wetlands – were introduced to North America well over 300 years ago. In Europe, where the plant is native, it supports 170 species of local herbivore insects, whereas it supports only 5 in North America. By contrast, “coastal panicgrass”, one of the keystone grasses being displaced by phragmites, supports 24 herbivore insect species.

With this lesson in mind, to create a Homegrown National Park, you should remove non-native plants and replace them with natives – especially native keystone plants.

The Norwich Conservation Commission has posted a native keystone plant list. Here’s what we suggest:

• Convert lawn (one of the most inhospitable areas to wildlife) to native plantings. Mow as little and as infrequently as possible to allow plants to flower and set seed.
• Do not rake leaves or pile mulch everywhere. Leaf litter improves soil and plant health. Insects need leaf litter, while bees need bare ground.
• When you plant native species, familiarize yourself with the exact Latin name of each plant, and make certain that is what you are getting. Common names overlap species and do not reliably inform you if you have the native variety.
• Avoid “improved species” and cultivars. Often they have characteristics, such as no pollen, or unfamiliar colors, that render them useless to native wildlife.
• If possible, buy plants or seeds from local ecotypes – plants or seeds whose “parent” was a wild plant growing in this general region.
• Buy organic plants – those raised from seed that was not treated with pesticides such as neonicotinoids. These chemicals persist in the mature plants and poison vulnerable bees.
• When you do establish a Homegrown National Park, you will learn to love the tattered, chewed-over plants in your garden in the fall. As you stroll your grounds, glory in the sounds and sight of native insects living among your plants.

A few top-supporting local Keystone Plants

Trees

Cherry: chokecherry, black cherry, pin cherry Birch: black, gray, paper, yellow birch

Oak: eastern white oak, northern red oak

Shrubs

Willow: Bebb, black, heart-leaved, prairie, pussywillow, shining

Blueberry: hillside, large, highbush, lowbush, velvetleaf

Alder: speckled

Flowers

Goldenrod: early, giant, gray, largeleaf, zigzag Strawberry: woodland, common

Sunflower: thinleaf