A perennial herbaceous plant up to 80 cm tall, with an erect and leafy stem, at the base of which are the fibrous remains of old leaves.
The leaves are basal, xiphoid in shape (as a result of which the species name is given), 1-2 cm wide, longer than the stem, with a silvery vein protruding in the middle of the leaf. The leaves of the wrapper are herbaceous, narrow-lanceolate, pointed.
There are 1-4 flowers on one bush, dark purple in color, velvety to the touch. The tube at the perianth is green, cylindrical, up to 1.5 cm long. Blooms in July - August. The fruit is a box with convex sides and notched ribs.