Purple Emperor, Sedum cauticola, Sedum spathufolium and Sedum sieboldii are varieties of Sedum. Other varieties of the perennial plant include Siberian Sedum kamtschaticum, Vera Jameson, Dragon's Blood and Angelina.
There are approximately 600 different varieties of Sedum indigenous to North America. A member of the Crassulaceae, or stonecrop family of flowering plants, Sedum varieties range from low-growing ground covers to tall herbaceous plants that deliver long-stemmed flowers suitable for cut arrangements.
Sedums are succulent plants that store water in their leaves. Some varieties of Sedum tolerate cold; others are hardier in warm climates. Sedum is an important source of food for butterflies.