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 or 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 not the time to control it unless it is in an area where a non-selective herbicide that kills everything such as glyphosate (Roundup) can be used. The best control for little barley in turf 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.
Overseeding in late August to early September can thicken up a tall fescue lawn and help prevent a little barley infestation. However, early germinating little barley may not be controlled. So, if you do not plan to overseed even though the lawn is a bit thin, pre-emergent herbicides can be used to provide at least partial control of this weed.
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 pre-emergence herbicide in mid-September and water in to activate. However, you may have to apply at least a couple of weeks earlier if you are in southern Kansas. If overseeding, do not apply any pre-emergence herbicide as it will interfere with the germination of tall fescue.
Alicia Boor is the Agriculture and Natural Resources agent with K-State Research and Extension – Cottonwood District. Contact her by email at firstname.lastname@example.org or call 620-793-1910.