Though its common name implies Irish origin, this plant is in fact native to the Mideast. To 23 feet high, 10 inches wide. Flowers are carried almost from base in whorls of six. Showy part of flower is its large, apple-green, shell- or bell-shaped calyx, very veiny and crisp textured; small white tube of united petals in center is inconspicuous. Blossom spikes are quite attractive and long lasting in either fresh or dried arrangements; be sure to remove the leaves, which are not especially good looking. Deer don't usually bother it.
Not an easy plant to grow in the South, as it dislikes hot, humid weather. Sow seeds in an empty planting bed in loose, fertile, well-drained soil in fall. Do not cover them with soilthey need light to germinate. Sow where you want plants to grow, as seedlings do not transplant well. In most areas, seedlings appear in spring. For long flower spikes, fertilize with a balanced water-soluble fertilizer every 2 weeks. In Florida and South Texas, seeds will germinate in fall (refrigerate them for a week before sowing), and the plant can be grown as a winter annual.