No Crown Vetch...Now
Glenn Nice, Weed Diagnostician,
Dept. of Botany
& Plant Pathology, Purdue University
For years crown vetch was recommended as a
cover crop for the purpose of soil erosion. Several people and
governmental organizations planted crown vetch to stabilize areas
where soil erosion would likely cause a problem. However, it
has been identified as a problem when invading natural areas.
Indiana’s Invasive Plant species
Assessment Working Group assessed crown vetch and determined that
it had a high potential for expansion [2, 3]. This has led to both
the Indiana Department of Transportation (IDOT) and the Indiana
branch of the National Resource Conservation Service (NRCS) in
dropping crown vetch from their recommendations . The web site
www.invasive.org, a web site that lists invasive and exotic species
describes crown vetch as “Once established it is difficult
“Well, if crown vetch is not recommended
anymore, what are the alternatives?” This is a question
that is often heard when the suggestion of not using crown vetch
is proposed. The purpose of using crown vetch is to slow the process
of erosion. Crown vetch forms a dense mat of vegetation and a tap
root system. This dense mat of vegetation absorbs the energy of
the rain and slows surface flow; however, although still fairly
effective for erosion control, the tap root system is not quit
as effective as a fibrous root system of some of the perennial
grass sods. The problem with perennial grasses is that they do
not establish quickly.
If the area is new, a place that has had recent disruption, strong
slope or a cover crop removed and it is at high risk for erosion,
the use of quick fixes may be required. Organic mulches, such as
wood fiber and straw, hydro mulch, erosion control blankets or
fabrics can be used as short term solutions while preparing to
seed a cover crop if needed .
In establishing your perennial
grass it is beneficial to use an annual grass mix to help stabilize
the soils while perennial grasses are being established. In the
NRCS Conservation Practice Standard it presently recommends planting
legume cool season grass mixtures in the spring from March 1st
to May 15th or in the fall from August 1st to September 15th .
If a dormant seeding is desired, plant from December 1st to March
1st. NRCS recommends planting a warm season grass and forbs mix
from April 1st to June 15th or December 1st to April 1st for a
dormant seeding. Legumes suggested are alfalfa, red clover, alsike
clover, birdsfoot trefoil, ladino clover and some lespedeza species.
Cool season grasses suggested by the NRCS are orchardgrass, tall
fescue, smooth bromegrass, timothy, and Kentucky bluegrass. Warm
season perennial grasses suggested are bluestems, Canadian wildrye
and indiangrass. See the Conservation Practice Standard for specific
seeding rates and species growing conditions.
In the crown vetch
facts sheet from the Indiana Invasive Plant Species Work Group,
alternatives to crown vetch are listed. Roundheaded lespedeza [Lespedeza
captiata], purple vetch [Vicia americana], Goat’s-rue [Tephrosia
virginiana, Virginia tephrosia], or creeping phlox [Phlox subulata,
moss phlox] are reported to be good native alternatives to crown
In the past we have looked to other parts
of the world for solutions to problems at home. In some cases
this has worked well; for example the introduction of soybean,
a plant originally from Asia. However, in other cases, it has
not worked out so well. Kudzu was originally introduced to the
US from Asia. It had been used in erosion control and as a possible
forage . Parts of the country, recently Indiana included,
have been fighting kudzu ever since. The intentions were good,
but the understanding of the species and how it would adapt to
our environment was incomplete. Kudzu, some honeysuckles, Japanese
silt grass, and other introduced species (either on purpose or
accident) have been identified as problematic and have fallen under
the category as being “Invasive Species.” In the case
of plants, the very characteristics that make the plant desirable,
ability to grow well, tolerate a wide variety of growing conditions
and ability to take a gamut of abuse, can also make the plant invasive.
For a list of invasive plant species in Indiana see either the
Indiana Cooperative Agricultural Pest Survey’s web site [http://extension.entm.purdue.edu/CAPS/]
or the Weed Science Page [http://www.btny.purdue.edu/weedscience/].
1. R.Y. Bailey. 1939. Kudzu for erosion control in
the southeast. Farmers Bulletin No. 1840. USDA.
2. Invasive Plant
Species Assessment Working Group. 2006. Crown Vetch Coronilla varia:
Invasive Plant Species Fact Sheet.
Accessed 1-20-2009. Crownvetch.
4. NRCS. Natural Resources Conservation Service Conservation Practice
Standard: Conservation Cover. pp. 327-1 to -8.
Accessed 1-21-2009. Soil Erosion Control: Mulches, Blankets and
Mats. Minnesota Urban Small Sites BMP Manual. (pdf file)
Click image to enlarge
All images taken from Invasive.org