Some species of fruit are commonly grown on their own roots: new plants are propagated by rooting, layering, or modern tissue-culture techniques. In some situations, special rootstocks may not confer any advantage or may be unavailable to the grower. Fig, filbert, olive, pomegranate, gooseberry, bramble, and other fruits are commonly grown without any special rootstock. Though vegetative propagation of apple, pear, stone fruits, and many other species is a nearly universal practice, it does have some detractors. Here is an account of one advocate of own-root fruit trees.