Page 130 - AG 7-2011 Revised 2016

Photo Courtesy of PBI/Gordon Corp. Quackgrass
(Agropyron repens)
Quackgrass is a blue-green perennial. The leaves are rolled in the
bud, The ligule is short and membranous, auricles are long and
clasping. The upper surface of the leaf blade is rough. Quackgrass
produces long sharp tipped aggressive rhizomes. Quackgrass
remains green year round.

The seedhead of quackgrass is a spike containing two rows of
spikelets. Awns are usually present.

Quackgrass is found throughout the Northern United States.

Immature Stage
Integrated Pest Management Control Recommendations
Cultural Practices:
Quackgrass is a problem of horticultural plants and turfgrass areas. Quackgrass can be introduced into turf areas
with the planting of ornamental trees and shrubs. Quackgrass is a problem in nursery areas. Once introduced into
turf areas, quackgrass spreads by aggressive rhizomes. Quackgrass is less aggressive in hot temperatures.

Herbicide Use:
Make your postemergent herbicide application to quackgrass that is actively growing and in the 2 leaf to flower
stage of growth. Control is only available with a non-selective control product.

MANAGE WEEDS IN ESTABLISHED LANDSCAPES
By Gary King, Ph.D.

Water and fertilize plants so they fill in and deny weeds the light they need; maintaining
the soil mulch layer also blocks out light. For more sparse plantings, apply a barrier of
appropriate pre-emergent herbicide prior to cool season weeds sprouting in the fall. Apply
in the early spring and again late spring to stop the seeds of warm season weeds from
sprouting.

No matter how conscientious you are, some weeds will still come up. These “escapees” must
be pulled by hand, hoed, or spot sprayed before any seeds form. Be cautious in directing
spot sprays only onto the weeds. Spray shields may be useful to protect ornamentals. For
the annual weed “escapees,” a contact-type post-emergent herbicide is usually sufficient to
kill them fully, but the perennial weed “escapees” will require an appropriate non-selective
post-emergent herbicide that translocates from the sprayed leaves to the root system or
growing points.

When plants are very dense, as in a groundcover or turf, you may be unable to direct
the sprays to the weeds without getting some spray on the desirable plants. Apply over-the-
top, application of a selective post-emergent herbicide as soon as weeds appear. With
such specialized herbicides, many broadleaf weeds can easily be eliminated from turf. Like-
wise, certain grass weeds can be killed from broadleaf plantings. Consult your Univar sales
staff for the best selection that will match your special weed problems.

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