Rattlesnake Master or Button Snakeroot or Button Eryngo or Tall Rattlesnake Master Apiaceae:
A perennial that reproduces only by seed. This is a very different but appealing accent plant that will grow well in difficult soils that are dry and hot. This species is a native of the central and eastern USA, where they are found in dry prairie eco-systems. The flowering heads look somewhat like Echinops ritro, but with a silver-white tinted blue color instead, the flowers age to an all silver white. The yucca-like foliage is long and thin and adds much to the over all presentation of the plants in the landscape. The leaves can reach 80 cm (2.6 ft.) in length. Best planted in groups of three with plenty of space between groups. Plants can grow from 3 to 5 feet tall and 12 to 24 inches wide; in moist overly rich soils they may need staking for the first year or two of blooming. Flowering occurs in July and August. Plants are long-lived under good conditions and may self-seed on open ground. E. yuccifolium is found throughout the eastern United States west to the Great Plains, but is rare in many localities - its listed as threatened or as special concern in Michigan, Minnesota and Ohio. The species name refers to the long, narrow leaves that look like yucca leaves.
Seeds respond best to cold moist stratification for three to five months. First Use 2-4 weeks at 68F, if no germination then move for 4-6 weeks to 25-39F, after move to 53-60F for germination.