Switchgrass

Switchgrass, or Panicum virgatum, has become increasingly popular in the past ten or fifteen years as an ornamental grass that is native to North America, as opposed to the previously used Miscanthus and Pennisetum species.  It's a terrifically useful plant aesthetically, but it also has scientific merits as well.  The plant has been used for phytoremediation as well as biomass.  

Grasses are amazingly evolved plants -- where most angiosperms have the apical meristem (the part of the plant that signals growth and cell production to the entire organism) located at the terminal leader of the plant, grasses evolved so that the apical meristem is located at the joint where new blades emerge from the sheath.  This is an adaptation in response to the grazing habits of mammals on the plains.  If, for instance, buffalo grazed on grasses and consistently chewed off the apical meristem, the plants would diminish quickly.  When the apical meristem is at a node closer to the ground, growth patterns are not interrupted by nearby herbivores. (Please note: I probably condensed several books' worth of science into a few sentences -- no doubt a better scientist could have explained this more clearly and accurately!)

The photos above are most likely of a cultivar of switchgrass called 'Shenandoah' which is notable for it's red foliage.  The shots above also show the panicle of flowers typically seen in late summer/early fall.  Panicum is a warm season grass, which means the plant grows most during hot, dry summers and has extensive root systems to allow them to survive drought.

The shot above and below is at the Christiana Mall in Delaware.  I think it is a good illustration of how a native prairie grass (though its distribution stretches from Nova Scotia to Mexico) can be used in a very corporate landscape.  I also think it combines beautifully with Hydrangea paniculata.

Panicum is derivative of the Latin word for millet, which is also the root for the word bread in French and Spanish, pain and pan, respectively. 

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.