Weed Management and Invasive Species Control - Project Planning and Management for Ecological Restoration - page 195

SEEDED GROUNDCOVERS NOT INSTALLED
If seeded groundcovers are not installed in the restoration area, it is generally for one of the follow-
ing reasons. The first is in a case where the area is small and weed control can be performed by
hand or an acceptable weedy groundcover exists. In this case, weed control can be limited to the
three-foot zone around installed plants, with periodic mowing or cutting of weeds within the site if
they grow tall and interfere with the success of the restoration or hamper maintenance procedures.
Only Priority 1 weeds would need to be eliminated.
Another example in which groundcovers would not be installed in a restoration area would
be where a thick organic mulch, such as straw, is used to suppress the weeds. This would be ef-
fective if the ground was weed-free before applying the mulch and the mulch was at least six to
eight inches thick. In such cases, ideally one would plant native, rhizomatous groundcovers and
encourage their spread as well as encourage the spread of any native groundcovers that “volunteer”
on the site. The elimination of Priority 1 species would be necessary, although control of Priority
2 species would be optional.
Weed Control Methods
Weeds can be controlled by a variety of methods, including burning, flaming, mowing, hoeing,
cutting, girdling, pulling, uprooting, tilling, smothering, mulching, applying herbicides, and in-
stalling weed mats. In the following discussion of weed control methods, a description of the three
main groups of weeds (annual, biennial, and perennial) is also given because control methods
differ for each group, except with the use of mulches and weed mats around individual plants
(discussed last).
Annual Weeds (Annuals)
Annual weeds live no more than one year. They germinate, grow, flower, and set seed in a mat-
ter of months. Annuals generally reproduce by seed. Two broad categories are summer annuals,
which grow in warm weather and survive as seeds during the winter, and winter annuals, which
grow during the cool season and lie dormant as seeds during the summer. Annuals should be
killed by cutting them off at least two inches below ground level by hoeing, pulling, and uproot-
ing. They may also be killed by repeated mowings or cutting off aboveground. Mowing or cutting
aboveground is most effective just as the plant is beginning to flower. However, if they recover, re-
peated mowing is required. Properly timed herbicide application can be highly successful without
involving an extensive amount of repeated labor during the growing season.
Biennial Weeds (Biennials)
A true biennial plant germinates and grows in its first year and then flowers, sets seed, and dies in
its second year. Biennials generally reproduce only by seed. Biennials sometimes act as annuals
and flower in their first year (although they usually will survive their second year as well) or act like