Japanese Stiltgrass – a weedy headache for our lawns and environment

By Gene Sumi  Homestead Education Coordinator 

I’m hearing customers say that a micro-bamboo has invaded their lawns.   Well, its technical name is Microstegium vimineum, but it has pick up many common names, such as Japanese stiltgrass, Nepalese browntop, basketgrass and Chinese packing grass.  The last name is appropriate since this weed grass is believed to have been introduced from Asia, where it was used as packing material for exported porcelain. 

Since it was first documented in Tennessee in 1919, Japanese stiltgrass has spread throughout the Northeast and mid-Atlantic states.  It’s an annual weed, emerging in spring and slowly growing to maturity by late summer.   It’s tolerant of shade and seems to take over the existing turf grass.

It is difficult to ignore this weed.  It can grow to 2 feet high or taller, and it spreads in large patches all over the existing lawn.  With leaves wider than turf grasses, it does resemble a miniature bamboo.  Another feature of this grass is that the midribs running down the center of the 1- to 3-inch leaf blades have a distinctive glossy sheen. 

Stiltgrass is extremely invasive and can quickly take over many open areas in parks, along roadsides and many places with open land.  It is considered to be a serious environmental threat as it crowds out native plants and often destroys them by completely overshadowing them, denying them enough sunlight to live.  Unfortunately, there are no known biological controls to keep them in check.  The stiltgrass patches found growing in lawns and beds can be spot-treaded with a glysophate herbicide such as Round Up.  One of the best ways to reduce the spread of this grass is to mow the lawn regularly in late summer to fall, before the weed’s tall, thin seed heads mature and the hundreds of new seeds can be dispersed to create new plants next spring.

Photo source (and for more information):  National Park Service.