Diospyros virginiana In respect to the power of making heartwood, the persimmon rarely develops any heartwood until it is nearly one hundred years old. This heartwood is extremely close-grained and almost black, resembling ebony (of which it is a true variety). It is a common misconception persimmon fruit needs frost to ripen and soften, called bletting. Some, such as the early-ripening varieties "pieper" and "NC21"(also known as "supersweet"), easily lose astringency and become completely free of it when slightly soft at the touch—these are then very sweet, even in the British climate. On the other hand, some varieties (like the very large
Blue tomato stems, where they are not eaten and would not provide any health benefit. With this in mind, researchers at Oregon State University have produced blue tomatoes using conventional breeding techniques, cross-pollinating domestic tomatoes with wild varieties that possess the "Anthocyanin fruit" (Aft) allele. As of the 2012 growing season, Oregon State University developed blue tomato seeds became commercially available under the cultivar name "Indigo Rose". The blue color is produced mostly by the anthocyanin petunidin on the outside of the tomato where the fruit is exposed to direct sunlight. The shaded side of the fruit is green when unripe, red