Ipomoea batatas - A really unusual variety of sweet potato with purple skin and purple flesh also. Tubers cooked as you would common sweet potato, but they are especially good for frying and roasting. Very high in vitamins and minerals, also potassium and antioxidants. The purple colour of the tubers also provides health benefits through its consumption. Purple Sweet potato prefers to be grown in a rich soil, in a sunny position and to be kept well watered. The tubers store well in a cool dry place. The leaves are not frost hardy and will die back with light frosts, but I have found the tubers to survive frosts here underground and re-shoot in the spring. These are sold as rooted slips, its best to soak the roots in water for a couple of hours before planting out.