Heirloom. Huge, glossy dark green white veined leaves are fleshy, crumpled and attractive. This is the best variety for greens as it always produces a bumper crop of tasty leaves – even during periods of high temperatures! Maintain sufficient soil moisture to keep plants from wilting. Try carefully removing leaves from the root crown. By doing this, new leaves will sprout for harvesting all summer long. Introduced in 1924.