Native Plants Have a Huge Role To Play, But What Qualifies As Native?

A discussion broke out about what is a truly native plant at a meeting of the Horticultural Alliance of the Hamptons Tree Initiative: Does honey locust qualify? It’s a great pollinator-supportive tree and divinely fragrant when in bloom, but it may not be native to the East End.

The HAH Tree Initiative began two years ago, inspired by the Trillion Tree Campaign and Drawdown. The goal is to restore the tree canopy of the East End with an emphasis on native trees. The initiative got a headstart on the United Nations Decade on Ecosystem Restoration, which began this year. The U.N. program, working with the Society for Ecological Restoration and other like-minded groups, aims to reverse the degradation of ecosystems worldwide. It promotes ways to improve native biodiversity and restore healthy environments for all living creatures. The HAH Tree Initiative is a positive, proactive and deeply engaged group that brings these high ideals down to street level.

Rich Bogusch from Bridge Gardens, a member of the Tree Initiative, writes for the HAH newsletter about native trees of all types: hickories, oaks, Sassafras, black cherry, sweetgum, etc. He countered the honey locust provenance. The native locust that settlers used for posts to hold up floorboards is black locust.

Tree Initiative members believe that we all can help combat the ecological crises we are facing, including the decimation of the numbers and variety of birds and insects.

Member Alicia Whittaker explained: “Gardeners have a huge role to play in restoring the wild food sources and shelter. Native trees and plants are important because they provide superior sources of food for our local insect and bird populations.”

What constitutes a native plant is the focus of ecological restorationists, conservation boards, arboretums, commercial growers, landscape professionals and homeowners. What plants are particular to the East End, and what plants are native to the Mid-Atlantic range more broadly? What is the difference, and does it matter? It’s a hot topic.

New England blazing star (Liatris scariosa var. novae angliae) was featured in biologist Don Lyman’s Boston Globe column this August. Zoo New England, Arnold Arboretum, Eastern Connecticut State University and MassWildlife propagated plants from local seed collected around New England to ensure that this beautiful purple-flowered perennial with high-quality nectar will proliferate. This is the gold standard of ecological restoration.

Jim Glover of Glover Perennials collects New England blazing star seeds that he then propagates at his nursery. In an email, he explained the importance of collecting the seed from plants that are already growing locally: “The local ecotype (or provenance, whichever you prefer) of a native species offers the best adaptation to the local environment including the local ecology, climate, soil chemistry and water availability. The insects, herbivores, birds, soil microorganisms as well as the soil type, weather patterns and microclimates all have an influence on the adaptation of a plant species to a particular locale.

“A little bluestem grass (Schizachyrium scoparium) from Nebraska or a swamp milkweed (Asclepias incarnata) from Utah will not have the same adaptations as one from Long Island, though they are the same species,” Glover continued.

Other local ecotypes Glover grows are Aster, Hibiscus, Iris, Pycnanthemum, Panicum, Solidago and Spiraea alba. These are native plants that flower from June to October and can be used in a perennial bed or a revegetation zone.

Glover is in tune with Seeds of Success, aka SOS, our national native seed collection program developed by the Bureau of Land Management and Kew Gardens. The SOS website explains its mission and protocols for collecting seed from wild populations: To make sure that wild populations are not diminished, no more than 20 percent of the existing seed production in an area is taken. Everything is carefully labeled for both time and place.

The Bureau of Land Management Native Seed and Plant Materials Development program is focused on increasing the quality and quantity of native plant species for resilient ecosystem restoration. There have been more than a few collection events across the East End, according to the program’s maps.

Scott Clark of Pinewood Perennial Gardens agrees about provenance: Where a plant originates from matters. Genetic characteristics develop over time based on the environment that a plant grows in.

Clark did studies of Liquidambar, the sweetgum tree. He grew trees from seed that originated in a wide range of climates, from New York to the Mississippi Delta. The seeds were all planted and grown in Pennsylvania, and regional differences quickly showed up in the young trees’ growth. The southern seed group did not respond to environmental clues like waning daylight the way the northern seed saplings did by leaves changing color and falling. Climatic differences determined regional variations in the seed.

Clark questions where seed is produced. “If it is grown from seed sourced out of our range, is it going to perform the same way in our environment as seed from our provenance?” he asked. “Through evolution, you get seed variation. You cannot just buy seed from a catalog. You have to ask, where did it originate from?”

Native plants are starting to sound like fine wines — the terroir is important.

Clark would like to see more flowering native plants that have ornamental value like the Asters that Glover grows. The best sellers at Pinewood are ferns and Panicum.

Another local nurseryman wonders about what epoch we are referencing when calling plant material “native.” Pre- or post-European settlement? There is a difference.

Local legend has it that whaling ship captains brought Rosa rugosa back from China. There was a shipwreck, and now this plant is pervasive, but not native. Long Island was considered the king’s woodlot. It has been cleared of timber at least twice.

Plant communities do not exist at a static point in time. The pine barrens are a good example of that. They are fire adapted but not pine beetle resistant. When the pines die out, other species will fill the gaps they leave. Climate change will also affect the species of trees in the forest.

New England blazing star grows in areas cleared by deforestation or fire. We see it here every year on the sandy sides of the roads. There is a large patch of Carex where Stephen Hands Path and Hands Creek intersect in East Hampton under a canopy of oaks that is probably not more than 100 years old.

Towd Point is crowned with Panicum and Schizachrium grasses, native cacti and cedar trees. Trout Pond is starting to reflect red-orange and gold as it is circled with maples, Clethra, Parthenosis, buttonbush and oaks. The black gums along the bridge by Lake Nowedonah in Water Mill are the first trees to turn a deep shade of reddish-purple that glows when backlit by the late afternoon sun. The fluffy white flowers of Baccharis line Meadow Lane and frame the vistas of the marshes that give way to dunes held together by beach grass, bayberry and beach plum. Blueberries light up in a multitude of colors throughout the local trails in the hills adored by hikers.

Zoning regulates clearing limits and what species can be used to revegetate overcleared areas based on ecosystem types like these local vistas. People can run afoul of the town by using the wrong plant material. Nurseries stock based on what the towns and landscape professionals specify and request.

Provenance is important but when a landscape project requires 40,000 perennial and grass plugs then this consideration may take a backseat to availability. Keeping native plant material in stock is a challenge.

A Westhampton nursery that specializes in beach grass recommends using more woody plant material like sumacs, beach plum, and true native roses Rosa caroliniana and Rosa Virginiana. For groundcover, use wintergreen and bearberry. Birch trees and Shadblow have become in demand along with American dogwood. Clethra can be seen all over the place in parks throughout Suffolk County, so the nursery suggests witch hazel, tulip trees and sweetgum to add variation and autumnal colors.

Buckley’s in East Hampton can’t keep enough bayberry around. Deer don’t eat it, it can be massed like privet and it can tolerate light shade. Rhododendron viscosum is an underappreciated native shrub along with buttonbush (Cephalanthus). They grow along the shoreline of local ponds and have fragrant white flowers in summer. Viburnum dentatum is a good woodland shrub that provides fall foraging. Magnolia virginiana is another summer-blooming suggestion from Buckley’s. White oaks, tupelos and Amelanchiers all do well. Nursery buyer Debbie Gates uses the local towns’ lists of native plants to pick out what she buys.

Demand is high and sometimes cultivars of a plant are used. Here the argument goes beyond what era and region the plant comes from to how the plant is produced. Panicum virgatum is propagated by seed, meaning there is genetic variation no matter where the seed is sourced from. Glover has a variety called Short Orient that is only 27 inches. Panicum Shenandoah at 4 feet, a named cultivar, is a clone. It is propagated vegetatively, so there is no genetic variation; they are all identical.

A Connecticut nurserywoman commented about the matter of what era native plants are from: Some plants were not here 100 years ago but existed 500 years ago. There are regional differences, but if something was wiped out by farming yet still grows elsewhere, shall we call it native or regional? Her father discovered an Ilex verticillata covered in red berries in Rhode Island. The salt marsh edge that it grew on and the ocean breezes that blew around it are all environmental conditions that the Ilex had to triumph in. To the nurseryman’s eye, this made it an outstanding selection for nursery production. Taking cuttings and propagating the Ilex led to a cultivar called Green Hill. The same family of growers had a bouquet of wild Clethra that was found to have redder stems, which once propagated became Clethra Anne’s Bouquet, a named variety. These plants are clonally reproduced instead of grown from seed and on paper they do not qualify as native, yet they have the same genetics as the original wild-growing Clethra and Ilex. As for what is truly native, they recommend Myrica gale.

Native landscapes are resilient, and they protect the groundwater. Long Beach and Accabonac Harbor are quick to recover from high tide inundation; wind and salt don’t kill the vegetation.

Native landscapes are fully adapted to the conditions that exist right here. Historically, they have been recorded by artists. Any given art show of local painters can clearly illustrate scenes around the bays, ponds and marshes that make up the backdrop of our lives — the beauty of the East End.

William Merritt Chase’s paintings of Shinnecock Hills from the late-1890s are awash in dreamy summer sunlight. “Gathering Wildflowers” and “A Summer Day” are evocative of a time and place. Native plants are depicted in his paintings symbolizing an idyllic summer afternoon, and the beauty of the local landscape. He chronicled the era of those sandy hills simply by painting what was there: little bluestem, bayberry, Asters, Asclepias, wild roses and Panicum.

In the 1960s, Robert Dash painted the fallow farm fields and roads of Sagaponack. The plant palette also shimmers in the aqueous, hazy summer light. He recorded the colors of the fields, the clarity or mistiness of the environment they thrive in. These are the same plants that the towns require homeowners to use for revegetation projects. They can be seen growing at Towd Point, Trout Pond or in the hills, along fields and pond edges.