Japanese Stilt Grass

Asked March 29, 2018, 10:00 AM EDT

I want to spray the Japanese stilt grass on my wooded half acre property. I primarily will be spraying he woods. Its a big job so I'm trying to make room on my calendar. When does the grass typically come in? When is a good time early in the season to spray? What spray is recommended? From What I've read the recommendation is spraying for five years due to the life of the seeds. Thank you in advance Heather Ebert

Durham County North Carolina horticulture weed management

1 Response

This question was answered by a Durham County Extension Master Gardener volunteer.

Hi Heather,

Thank you for your interesting question. It's one on many gardeners' mind this time of year.

Japanese stiltgrass germinates in early spring, March to early April and flowers from mid-September through October.

The trick is to keep it from flowering in the first place. At least some of the flowers are self-fertilized even before the flower opens. They can produce a copious amount of seed that remains viable up to seven years. So long term management programs should emphasize prevention of seeded formation to deplete the seed reservoir.

Regular, close mowing beginning early in the season and kept up during the year is important.

Very few herbicides are specifically labeled for Japanses stiltgrass control. Furthermore, few herbicides are labeled for use in the wet woodlands where this weed is common. However, most preemergence and postemergence herbicides used for crabgrass control in turfgrass and landscape plantings are effective on Japanese stiltgrass.

A combination of a reemergent, such as Preen, mowing, and a post emergent, such as glyphosate is the most effective way to control and eventually eliminate Japanese Stilt Grass.

** Before using any herbicide, read the label and follow all label directions and restrictions.

For more information, please go to the North Carolina State Extension website:


We're glad to be of help and please contact us again.


Sara Smith, EMGV

Durham County Extension Master gardener

721 Foster Street

Durham, NC 27701