By Roger Witherspoon
The Journal News (Westchester County, NY)
September 6, 2003 Saturday
Westchester project aims to show local species' advantages
The Journal News
In the view of Westchester County officials and other proponents of native plants,
the best way to prune a Norway maple is with a woodsman's ax.
That's exactly what the county may do in a few years, as the parks department
aggressively moves to replace invasive plants with native species in its 16,000 acres
of parkland. The county, along with the curators at the Teatown Lake Reservation in
Yorktown and the Native Plant Center at Westchester Community College in Valhalla,
is on a mission to demonstrate the vitality and variety of native plant species and
their effect on the environment.
"We hope to find which native species survives best in a region," Deputy Parks
Commissioner Jack Robbins said, "and we will expand that kind in that location and
try that combination in other parks. One of the virtues of native plants is that they
are hardier and can do a better job holding their own against some of the more
savage invasive plants, such as purple loosestrife."
For the past two years, the parks department has planted only native shrubs, flowers
and grasses while removing invasive plants that can choke and take over natural
habitats and other species. Japanese knotweed and porcelain berry, for example,
were replaced with black-eyed Susans and little bluestems at the Read Sanctuary in
Rye. At the Nature Study Woods in New Rochelle, the same foreign plants were
removed in favor of young red and silver maples, sycamores and swamp white oaks.
The "Go Native" program developed by the department, in conjunction with the
Native Plant Center and the Federated Conservationists of Westchester County, also
encourages residents to replace non-native plants with those that evolved in the
county. Most of these species are locally grown and naturally produced, as opposed
to the mass-produced male clones shipped here from Midwestern nurseries, which
produce excessive amounts of pollen.
Native trees, shrubs, flowers and grasses are an integral part of the region's
ecosystem, and the presence of invasive plants alters the pattern of wildlife.
"When you lose native plants," said Tess Present, director of the community
conservation program for the national Audubon Society, "you lose the food supply
and shelter areas in which insects and birds can spend the winter. Many plants, such
as the highbush cranberry, have fruit available in the winter and are very good for
local wintering birds, such as the bluebird and brown thrasher."
Planting native flora in parks and preserves is important, Present said, but "it is
increasingly clear that we need to protect the areas connecting them - and that
means our own property and yards need to have native plants."
Shade trees like the Norway maple, for example, are damaging to the local
environment, said Leah Kennell, curator of Wildflower Island at Teatown. "It's a
really horrible example of a non-native species. It has enormous leaves which take a
lot of sunlight and are damaging to smaller trees and shrubs."
The leaves are far more alkaline than those of native trees, she said, so when they
fall and decompose during the winter, they alter the chemical balance of the ground,
hampering the development of new plants in the spring.
"If you want a maple or other shade tree, there are plenty of native trees available,"
Kennell said. "You don't need European or Asian trees."
There also are economic benefits to planting native trees and flowers, said Tedor
Whitman, Teatown's director of education. "They take less upkeep once they are
planted because they are part of the local biological diversity and are built into the
local ecosystem. You don't need to invest in pesticides to protect them."
Brooke Beebe, project director at the Native Plant Center, said native plants are
hardier than others because they are naturally adapted to the local climate, diseases
and pests. "A plant which evolved here is used to our droughts and wet times and
will thrive," she said.
In addition, there are symbiotic relationships between some plants and insects -
particularly bees and butterflies - and they need each other to survive. "The monarch
butterfly only lays its eggs on the leaves of the milkweed plants," Beebe said, "and if
the milkweed disappear, there will be no monarch butterflies. They will sip nectar
from other species of plants, but they will only lay eggs on the milkweed."
Teatown's 2-acre Wildflower Island is dotted with long, blue New York ironweed,
which is essential to the survival of the gold-banded and silver-spotted skipper
butterfly. "Certain butterflies require local flowers because of their joint evolution,"
Whitman said. "The skippers' mouth parts are specifically designed for these flowers.
If you plant native flowers, instead of tulips and other plants they have never seen
before, the local butterflies will suddenly come back."
The Native Plant Center maintains two gardens with about 75 species of wildflowers,
shrubs and trees. Beebe said when residents purchase plants for their homes they
should specify that they want native plants that are not male clones.
"You want the plants around your home to be as natural as possible," she said. "It
will help you, and it will help the environment."
Reach Roger Witherspoon at firstname.lastname@example.org or 914-696-8566.
Native plants info
* The Native Plant Center at Westchester Community College
* Teatown Lake Reservation
* Westchester County Parks' Nature Centers
* Cranberry Lake Preserve: 428-1005
* Croton Point Park: 862-5297
* Lenoir Preserve: 968-5851
* Marshlands Conservancy: 835-4466
* Read Sanctuary: 967-8720
* Trailside Museum: 864-7322
* Cornell Cooperative Extension Service
* Westchester County, Valhalla: 914-285-4640
* Putnam County, Brewster: 845-278-6738
* Rockland County, New City: 845-429-7085
* Audubon Society