of Rhode Island GreenShare Factsheets
Nutsedge, or "nutgrass", Cyperus esculentus, is
a lawn weed with erect triangular yellow-green stems and narrow,
grass-like leaves originating at the base of the plant. Its
seedhead is yellow-brown in color. Nutsedge is an adaptable
weed that makes its home in low ground along water courses
or in rich sandy soils where gardening is practiced. It is
a triplet species because it can reproduce from a perennial
base, nut-like tubers beneath the soil surface and by seeds.
The nut-like tubers are what make nutsedge difficult to eradicate.
If the plant is not completely removed from the soil and the
tubers remain, they can produce new plants in your lawn.
The greatest source of weed seeds in new lawns is the soil itself. Planting
at the proper season with the right grasses and adequate fertilization
at seeding time are the most important practices in minimizing weed problems.
In the Northeast, late summer (August 20 - October 1) planting is almost
the only means of preventing nutsedge from taking over the lawn. When planted
in late summer, the grass plants will spread laterally and the turf will
be dense and mature before most troublesome lawn weeds appear.
Most common lawn weeds can be greatly reduced by improved lawn care, including
proper fertilization and mowing. Sometimes, however, weeds persist in spite
of good maintenance.
For small lawns or where there
are only a few weeds, hand pulling as weeds appear can give
good temporary results.
Weeds can be pulled more easily after a heavy rain or watering.
The use of herbicides to control weeds is more practical for
large areas, more difficult-to-pull weeds and small patches
of persistent weeds. Large areas can be treated with sprays
or granules, which give good weed control with minimal injury
to turfgrass. Single clumps of weeds can be spot treated. Aerosol "spot
weeders" are available for such areas. When weeds infest an
area of any size and the populations are high enough throughout
the area to be objectionable an overall treatment with a selective
chemical that will kill the weeds and leave the grass unharmed
may be necessary. Where weed infestation is serious and the
turf is poor, consider renovating the lawn.
Check the herbicide label for the proper way and most
effective time to apply herbicides.
To minimize weed problems:
- Select the recommended grass for your site
- Plant your new lawn in the late summer
- Use adequate fertilizer (and limestone if needed), especially
when starting a new lawn
- Mow your lawn to a height of at least 1-1/2 inches to better
compete with weeds
- Control diseases and insects that damage turf and allow weed
- Water the lawn deepl andthoroughly, not too little too often
If necessary, apply bentazon (Basagran) in late
June to early July; repeat in 10 to 14 days if necessary. The
high rate has injured ryegrass turf; avoid such applications
during hot weather to minimize the chances of injury; or apply
halosulfuron (Manage) at the 3- to 8- leaf stage with an nonionic
surfactant. A second application may be needed 6 weeks later;
or apply methanearsonate (MSMA) when first active spring growth
occurs. Repeat the application in 10 to 14 days. It may discolor
Adapted from Tom Kowalsick,
Cornell Cooperative Extension, 2001
are poisonous! Read and follow all safety precautions on labels.
Handle carefully and store in original containers out of reach
of children, pets or livestock. Dispose of empty containers
immediately, in a safe manner and place. Pesticides should never
be stored with foods or in areas where people eat.
When trade names are used for identification, no product endorsement
is implied, nor is discrimination intended against similar materials.
Be sure that the pesticide you intend to use is registered for
the state of use.
The user of this information assumes all risk for personal injury
or property damage.
information, call the URI CE Gardening and Food Safety Hotline
at 1-800-448-1011 or (401)874-2929 from outside Rhode Island;
Monday-Thursday between 9 am and 2 pm.
of Rhode Island Cooperative Extension provides equal program