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Little Barley in Lawns

Stacy Campbell
K-State Research & Extension

The  Ellis County Master Gardeners and IKSU research & extension are currently filling in for Holly while she is on maternity leave. Before Holly left she mentioned to me that if I wanted to write about a horticulture topic–how to control little barley would be very timely.

Many people mistake little barley (Hordeum pusillum) for a little foxtail because the foxtail and little barley seedheads are similar. However, little barley is a winter annual that comes up in late September – October and spends the winter as a small plant. It thrives in the cooler spring temperatures, forms seed heads and dies out usually by July. Foxtail, on the other hand, is a summer annual that does well in hot weather. Also, foxtail will not produce seedheads until mid- to late-summer.

So why are we talking about little barley now? Because now is the time to control it for next year, according to K-State Horticulturist Ward Upham.

The best control for little barley is a thick lawn that is mowed high enough that sunlight does not hit the soil. Little barley seed will not germinate in such conditions. Over-seeding now can
thicken up a tall fescue lawn and prevent a little barley infestation. However, if you do not plan to over-seed, preemergence herbicides can be used to provide at least partial control of this weed.

The only preemergence herbicide that I know is labeled specifically for little barley is Surflan. It
is also sold under the name of Weed Impede by Monterey Lawn and Garden. Surflan can only be
used on warm-season grasses (bermudagrass, buffalograss, zoysiagrass) and tall fescue grown in
warm-season areas such as Kansas. However, Dimension (dithiopyr), is labeled for barley
(Herodium spp.) which would include little barley and therefore can be used to keep this weed
under control. Because little barley is a winter annual, apply the preemergence herbicide in
September and water in to activate. If overseeding, do not apply any preemergence herbicide as
it will interfere with the germination of tall fescue.
Fertilizing cool-season lawns
For cool-season lawns, most of the fertilizer should be applied in the fall. Fescue and bluegrass benefit most from fall-applied nitrogen applications. September is the most important time. Nitrogen (N) applied during September helps thicken the stand, and encourages development of a healthy root system. A November application (at about the time of the final mowing of the season) helps the turf build food reserves. This enables the lawn to green up earlier in the spring, without encouraging the excessive shoot growth that often accompanies early spring N applications.
This emphasis on fall fertilization may seem strange, especially since some garden centers and stores vigorously promote their fertilizer products in the spring. But cool-season lawns characteristically experience a flush of shoot growth sometime in mid-spring. Applying N before this flush is over can cause the grass to grow too fast. The shoot growth exhausts the plant’s food stocks, and leaves it with little in reserve for the stressful summer ahead. So it is best to wait until the flush of shoot growth is over, normally early in May, before making spring-applications of N. Ideally, a slowly available N source would be used for the May application. This encourages moderate, controlled growth as the hot summer weather approaches. If a late June or early July application is deemed necessary, use a slow-release N source and keep rates on the low side ½ to 1 lb./1,000 sq. feet. Excessive N during the summer can potentially lead to disease problems for cool-season grasses.

KSKOLLECTIONJULYAUG

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