Stiltgrass is Everywhere

Japanese stiltgrass, late July 2017 (photo by Kate St.John)
Japanese stiltgrass, late July 2017 (photo by Kate St.John)

This summer I’ve found a lot of stiltgrass in western Pennsylvania.

Japanese stiltgrass (Microstegium vimineum) is a native of Eurasia that grows in both sun and shade.  In the 1900s it was used as packing material for shipping porcelain from China to the New World.  Inevitably, it took root in Tennessee in 1919 and is now present in 24 states and Puerto Rico.  In Pennsylvania it’s invasive, especially in the woods.

Though grasses are notoriously difficult to identify, stiltgrass has three characteristics that help you figure it out.

(1) Each leaf has a shiny central rib, as shown above.

(2) The rib is off center on the leaf, easiest to see on the underside.

Back of the leaf: Japanese stiltgrass (photo by Kate St.John)
Underside of the leaf shows the off-center rib on Japanese stiltgrass (photo by Kate St.John)

(3) Unlike native grasses, stiltgrass forms a dense carpet on the forest floor that chokes out all other plants.

Japanese stiltgrass, late July 2017 (photo by Kate St.John)
Japanese stiltgrass, late July 2017 (photo by Kate St.John)

When you see dense grass like this, check it for shiny off-center ribs.  Watch this video for more identification clues.

This year I’ve seen stiltgrass at all the bike trails and even in the woods in Schenley Park.  It looks like a nice carpet until you realize it’s invasive.  It’s everywhere!

How do you get rid of it?

Deer don’t eat it.  But goats do.   Hmmmm.


(photos by Kate St. John)

2 thoughts on “Stiltgrass is Everywhere

  1. Hi Kate it is easy to pull and does not seed until late summer so pulling it may slowly make a difference.. I’ve been pulling it in my yard a few minutes a day since identifying it a couple years back; it showed up after I took out my Japanese pachysandra to make way for jewelweed and clearweed – think it’s starting to help….

  2. Stiltgrass is unusually difficult to get rid of, forest management techniques (such as controlled burns) just ‘make it mad’ and the plant responds by growing faster! It can also take root from the nodes along its stem (hence the carpet effect). By pulling it in late summer (when it is tall but before it sets seed) and then re-seeing the area with native plants, you might be able to make progress (pull while the soil is moist, if you tear the roots it will sprout with vigor). It likes cool, moist areas, so opening up the upper canopy (trimming back some tree branches) and not watering it might help too. Be prepared to fight it for years, even though it dies back over the winter, the seeds from previous years can survive in the soil for years, just waiting for cool, moist conditions to occur so it can sprout up and race over the area.

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