Horsetail Reed

Scouring rush (Equisetum hyemale, Equisetaceae) is a non-flowering vascular plant native to broad regions of the Northern Hemisphere, reaching 3 to 5 feet tall. Upright, jointed, bamboo-like stems (about 0.5 inches in diameter) are dark green, rigid, and impregnated with silica, giving the surface a rough, scouring texture. The plant produces no true leaves or flowers, reproducing by spores.

Scouring rush grows in sun to part shade on moist soils (pH 4.5 to 8.5), hardy in Zones 3a to 11b. It is an aggressive spreader via deep rhizomes and can be very difficult to eradicate once established; container culture is advisable. Large quantities are toxic, containing the enzyme thiaminase. No cultivars are in the trade.