Phragmites australis

I have been spending a lot of time traveling between DC and Philly lately and finally decided to take some very quick snapshots of the Phragmites australis stands I pass when driving through Delaware.  If you have even a passing knowledge of landscape design or horticulture, chances are you know this noxious weed.  

 

The story goes that Phragmites was brought to this continent in the early 20th Century in the form of packing material.  But, what may have been an innocent, reed-like plant in Europe has been destructive to many wetlands here in the United States.  Phragmites is tenacious, growing in wetlands with as much as 3' of water, to areas where the soil is merely damp.  Runners can travel as much as 15' in one growing season.  It's an incredibly common plant along highways -- the drainage ditches along the sides of 95, from Maryland straight up to the Meadowlands in New Jersey, are densely populated with this species. 

 

The plant is also halophytic, which means it tolerates some alkalinity in the soil (which means it can handle growing amongst crushed concrete and other demolition debris) and it also grows well in brackish water, so it's often seen in tidal estuaries, competing with our native salt marsh plant, Spartina. 

For a long time, it was assumed that Phragmites was only an invasive, exotic species, however recent research has indicated that there is also a native species of Phragmites (P. australis subspecies americanus).  This plant is evidently less virulent but physically only distinguishable as separate due to its shorter ligules.