NZ Grown Cert Organic Purple Skinned & Flesh Kumara - Purple Dawn or Radical
Okinawans have grown an unusual variety of sweet potato since the early 16th century. It was probably introduced by traders from the Philippines who had acquired them from the Spanish colonists who had brought these South American tubers across the Pacific.
Kumara(sweet potato) are a species of convolvulus vine, Ipomoea batatas, with typical morning glory flower and arrowhead-shaped leaves. The roots swell with stored starchy carbohydrate so the plant can survive winter, drought or cyclone damage and send up new shoots when conditions improve.
The purple colour is due to the anthocyanins in the tubers. These chemicals are the same ones occurring in blueberries, red and purple grape skins, as well as many other purple and red fruits and leaves.
June is harvest time for the best kumara I have ever tasted. It's the amazing purple-fleshed sweet potato from Okinawa. This purple-fleshed sweet potato has white skin and the flesh is veined with bright royal purple when freshly cut but the flesh turns entirely purple when cooked. They are just as easy to grow in New Zealand as our own popular kumara varieties. (See expert tips on how to grow kumara.)
The young shoots and leaves of sweet potato are edible.
Most New Zealanders don't realise that the young shoots and leaves of sweet potatoes are also edible. You always see bundles of these greens for sale in Asian and Latin American markets and they can be eaten fresh, steamed or in stir-fry dishes. The purple form has brighter purple veins at the leaf base than the common red-skinned New Zealand variety 'Owairaka'.
Growing purple Okinawan kumara is just the same as other types we grow in New Zealand.
* Young shoots that sprout from last summer's tubers can be pulled off when they are 15cm to 20cm long and put into a glass of water till they make roots.
* Or you can simply take cuttings from the old runners at harvest time. The cuttings grow roots within a week or so.
* Commercial growers start with tubers embedded in a box of damp straw in a plastic bag sitting in a warm spot so the young shoots grow roots as they emerge through the straw.
* If you're just starting out with your first Okinawa purple kumara, grow it as a houseplant in a sunny spot indoors through the winter.
Harvesting should be as late as possible in autumn so the tubers mature fully and store better.
They have become popular in Hawaii and the warmer southern states of the US over recent years, and they are here too. They really are the best kumara I've ever eaten.