This horsetail overwinters.

Stems  7 to 86 in. tall, 0.5 in thick at base; erect, evergreen, and usually unbranched.  Second-year stems more likely to branch than first-year stems, as are stems with tips damaged in some way.  If present, branches tend to be nearly vertical.  Fertile and sterile stems are alike.  Sheath 1 to 2 times longer than wide; tight to stem, green at first, then gray with dark bands at base and top.  Sharp-pointed,  brown-edged teeth usually soon wither and disappear.

Cavities  central cavity 2/3 or so of stem in diameter.  Vallecular canals much smaller than central cavity.

Cone  0.5-1 in. Short-stemmed, with sharp-pointed tip, maturing in summer.

Rhizome  branching and widely creeping.

There are no branches off the main stem.

S-rank:  No rank
G-rank:  G5 (Secure)