|Vigorous perennial (that you may want to confine)
with basal clusters of lance-shaped, somewhat spiny dark green leaves. Spikes of light yellow to light green flowers appear from late spring to early summer. Reaches 6 to 14 inches tall to 12 inches wide. Cut back flower stalks after flowering, leaving foliage. Divide foilage from October to March. Prefers shady situations and occasional deep watering, but tolerates sunny, dry situations too. Its aggressive roots make this plant perfect for slopes.