Invasive Plants: Mile-a-minute and Japanese Stiltgrass


Invasive species, habitat destruction and global climate change are leading causes of environmental degradation and loss of biological diversity worldwide.   The primary reason to know and control invasive species is their direct threat to native species.  Where invasive species take over native plants no longer thrive and the insects and animals which rely on these native plants are likewise lost.  On our blog we'll be highlighting particular invasive plants that are common in our area.  Pull them when you see them and share this information with your neighbors and friends.    Below are excellent resources for learning how to identify and remove invasive plants.
Photos and information on invasive plants, insects, animals, and diseases.
Mid-Atlantic Invasive Plant Council     A compilation of multiple lists for Maryland and neighboring states highlighting currently problematic invasive species


I've just come in from pulling this plant on a neighboring property (my good deed of the day).  The name tells you why this is an invasive plant.  It may not grow a mile-a-minute but it seems to as on really good day it can grow 12+ inches, 30 feet in a month or so.  The good news.  It is an annual and has shallow roots, so if you get out there in early June and pull it as it gets started, it is relatively easy to control.  And it hasn't been growing in our area for long.  The bad news.  If you let it grow it will climb over everything else and take over.  It also sets seeds (~500 per plant) which are dispersed by wildlife, wind, rain, and lawnmowers.  Take a seemingly innocuous 5 plants growing 12 inches a day and multiply by 500 (if left alone) and a potential 2,500 new plants enter our ecosystem.  

Persicaria perfoliata is a synonym for Polygonum perfoliatum, with common names like mile-a-minute weeddevil's tailgiant climbing tearthumb,and Asiatic tearthumb. It is a trailing annual vine with barbed stems and triangular leaves. It is native to most of temperate and tropical eastern Asia, from eastern Russia in the north down to India in the south.

Water is an important mode of dispersal. Its fruits can remain buoyant for 7–9 days, an important advantage for dispersing seed long distances in stream and river environments. The long vines frequently hang over waterways, allowing fruits that detach to be carried away in the water current. During storm events the potential spread of this plant is greatly increased throughout watersheds.(info and photos from Wikipedia)

Introduced in the U.S. by a nursery in Pennsylvania about 55 years ago, it has since spread to cover ~300 mile radius and growing.  If we all pull together we can rid our area of this noxious, alien weed.  Please share this information with your neighbors.

Japanese Stiltgrass, Microstegium vimineum

This invasive shows up almost everywhere in our area -- even on remote nature trails.  I've seen many yards where it has essentially replaced the turf grass.  The good news is that it is very easy to pull if you catch it when it first invades.

Japanese stiltgrass was introduced into the United States in Tennessee in 1919. It is currently established in 16 eastern states, from New York to Florida.  It can be found in full sun to deep shaded forest conditions.  Stiltgrass invades disturbed shaded areas, like floodplains that are prone to natural scouring, and areas subject to mowing, tilling and other soil-disturbing activities including white-tailed deer traffic. It spreads to form dense patches, displacing native wetland and forest vegetation as the patch expands. It is an annual grass resembling a small, delicate bamboo; mature plants grow to 2-3 ft. in height.  Spreads: by seed and by rooting at joints along the stem—a new plant can emerge from each node; a single plant can produce 100-1,000 seeds that remain viable in the soil for at least three years, ensuring its persistence; seed germinates readily following soil disturbance.  Because it is similar in appearance to several native grasses, it is important to know how to recognize and differentiate stiltgrass from look-alikes. Attention to new infestations should be a priority. Because it is shallow-rooted, stiltgrass may be pulled by hand at any time.  For extensive infestations, herbicides are the most practical and effective method currently.  (from