Green foxtail

Setaria viridis

At a glance
Type	Grass
Life cycle	Summer annual
Family	Grass family (Poaceae)
Origin	Introduced from elsewhere
Most common in	Northeast, Midwest, Great Plains, Mountain West

About

A summer annual grass with soft, bristly, bottlebrush seedheads. It's mostly a problem in gardens, new lawns and bare ground, since thick turf crowds it out.

Also called green bristlegrass, foxtail

How to identify it

Look for

Bright green clumps with flat, mostly hairless leaves; the leaf sheaths have fine hairs along their edges, and the ligule is a fringe of hairs. The seedhead is a dense, green, cylinder-shaped spike up to about 6 inches long with long bristles. Stem bases are often reddish purple.

Look-alikes

Yellow foxtail has long hairs at the base of the leaf and a yellowish seedhead, while giant foxtail has the biggest, drooping head.

Where it grows

Vegetable gardens, new lawns, roadsides, field edges and other bare or disturbed soil.

When

Sprouts from spring into midsummer once soil warms to about 65 degrees F, forms seedheads from July to September, and dies after frost.

How it spreads

Spreads by seed, and each plant can make thousands of seeds.

Most common in

Northeast	Very common here
Southeast	Common here
South Central	Common here
Midwest	Very common here
Great Plains	Very common here
Mountain West	Very common here
Southwest	Common here
Pacific Northwest	Common here
California	Common here
Alaska	Occasional here
Hawaii	Not found here

What to do, gentlest first

Start at the top. Weed killers are a last step; always read and follow the label.

Keep lawns thick and beds covered Prevent
Foxtail mostly takes hold in new or thin lawns and bare soil. Fertilize and water to keep turf dense, and avoid bringing in soil from weedy sites.
Pull before seedheads ripen By hand
Hand-pull or use a trowel on single plants, and hoe seedlings in the garden before they flower.
Bag plants with seedheads instead of composting them.
Mulch garden beds Barrier
Almost any mulch helps block foxtail seedlings in vegetable and flower beds.
Corn gluten meal before seeds sprout Organic spray
Corn gluten meal is labeled to stop foxtail seeds from sprouting. Spread it in early spring and water it in lightly; it won't affect plants that are already up.
Don't use it where you plan to sow seed.
Spring pre-emergent; quinclorac for young plants Conventional spray
In lawns, a spring pre-emergent such as prodiamine, pendimethalin or dithiopyr stops seedlings. Quinclorac or fenoxaprop can treat young plants in lawns.
Read and follow the label. Many lawn herbicides kill garden plants, so keep spray and drift off beds and vegetables.

Uses, wildlife and pets

Pets

Not listed as toxic to dogs, cats or horses by the ASPCA.

Sources

Photo: Photo: Rasbak / Wikimedia Commons, CC BY-SA 3.0 (CC BY-SA 3.0). Photo resized for the web.

Planting dates and advice are general guidance; check with your local Cooperative Extension office for your area.