Using Native Plants to Improve Water Quality
It started with the flame chub—a brightly colored 2- to 3inch long minnow. The tiny fish lived in a stream that
flowed through much of the common area of the
subdivision when Mike Ryon, an aquatic ecologist in the
Environmental Sciences Division, moved there.
Ryon describes the stream as he found it: “When I moved
there in 1994, the stream was typical of many urban
streams. There were no
trees or shrubs along the banks, just non-native fescue
grass that was kept mowed very short.” Improving the
environment for the rare chub meant protecting the
stream.
“Streams in East Tennessee need to have a buffer of trees
and shrubs in order to function naturally. The vegetation
helps shade the water keeping it cooler; tree and shrub
roots (because they are more complex and longer than
fescue roots) filter out contaminants (e.g., pesticides or
oils) and silt; the roots also armor the bank to keep it
from eroding away. The vegetation provides food, either
directly through leaf fall or as growing areas for insects.
A buffer of trees and shrubs also helps terrestrial animals
like migrant birds and mammals by providing habitat for
them.”
Flame chub (Hemitremia flamea)
Photography-- Richard T. Bryant
Ryon and neighbors plant first
trees
After getting approvals from the homeowners’ association, he planned a riparian buffer
between the lawns and the stream. The Tennessee Valley Authority gave him about
$2500 in a watershed grant, which he used to buy plants—several good-sized native trees
and less-expensive native small trees, shrubs, and non-woody plants. After the initial
planting, the effort continued. Both neighbors and the homeowners’ association have
helped with improvements and
maintenance. Boy Scouts in search of
Eagle Scout projects and community
service hours have removed invasive, nonnative plants and landscaped a trail near
the stream.
Stream in 1999 before new plantings
The neighborhood has taken responsibility
for maintenance under the Farragut Adopta-Stream program. Stream clean-up days
are scheduled periodically. Over the years,
they have created a protective zone (25 to
100 feet wide) on each side of the stream.
This zone produced valuable habitat and made the stream representative of good East
Tennessee waterways. The planted area also reduces the area the association has to have
mowed, saving fuel and reducing emissions.
Ryon serves on the ORNL Landscaping
Committee, working particularly with
ponds and streams. He has gained an
appreciation of the advantages of using
native plants and an increased knowledge
of what is available. He often helps with
community projects and provides
information on native plantings to schools
and parks.
The next improvement planned for the
Stream area with early plantings in 2001
neighborhood stream is the addition of a
“rain garden.” There is a parking lot next to the stream, with a concrete channel to the
stream that drains the runoff from the parking lot. The concrete will be replaced with a
series of small depressions, planted with water-tolerant plants, between the parking lot
and the stream. The plants will slow the progression of the runoff to the stream, allowing
more time for contaminants to settle out in the depressions or be filtered out by the plants
before the water gets to the stream.
Ryon suggests that you may want to start “small” when beginning to landscape with
native plants. While native species should be better adapted to the local environment
(e.g., climate, pests, soils, etc.), some plants will do better than others in your specific
location. Nurseries that sell native plants and seeds provide plenty of ideas. Or you could
check the list of native species approved for planting on the Oak Ridge Reservation.
Sources for native plants:
Sunlight Gardens, near Clinton, TN,
865-494-8237,
http://www.sunlightgardens.com/
Overhill Gardens, Vonore, TN
423-295-2288,
http://www.overhillgardens.com/
Lush growth protecting stream in 2010
Ernst Conservation Seeds, Meadville, PA,
800-873-3321, http://www.ernstseed.com/
Other sources can be found by searching
online for native plant nurseries in
Tennessee.