White mulberry (Eng); morera, morera blanca (Spa); morera blanca, morer blanc (Cat); masustabe, marhugatze (Baq); moreira branca (Glg); amoreira-branca (Por).
"Kublai Khan commanded the minting of money from the membrane found between the bark and trunk of the mulberry".
The travels of Marco Polo
A deciduous tree up to 18 m tall, with smooth grey bark when it is young, but which becomes thick, very cracked and brown or grey with age. The leaves are deciduous, simple, and alternate. They are 3 to 22 cm long, with the width being a little less than this, and very variable in shape: they can be oval, rounded or lobed, with two or more lobes, but always toothed along the margin. They have long stalks that are a little hairy and sometimes exude latex when crushed. They are thin, usually finishing in a tip, heart-shaped at the base and commonly hairless. On the upper side they are shiny, and the underside may have a few hairs between the veins. These features, together with the long-stalked fruits, which when ripe are rather bland and usually white, white-greenish or pinkish in colour (although they are occasionally red or black), differentiate this species from the black mulberry, Morus nigra. The flowers are not very showy and are unisexual, i.e., either male or female. They are usually found on different plants, but sometimes they are separated on the same tree. The fruit should really be called an infructescence, because it is complex and each small ball is a true fruit. These group together to form a structure similar to a blackberry, known in botany as a sorosis. The white mulberry is, however, completely different, because the blackberry is in the rose family (genus Rubus).
Mulberry trees are indifferent to soil type, though they grow best in deep, fertile substrates and do less well on highly acidic ones. This species is very tolerant of pollution, severe pruning, and the rigors of cold and heat, provided there is not a prolonged lack of water. The white mulberry is usually cultivated in orchards and grown along walkways as an ornamental. It tends to become established in the wild close to towns on the midslopes, or medianías (zones between altitudes of 600 and 1500 m).
It is believed to be native to central and eastern Asia: China, Korea, Mongolia and northern India, although it is very difficult pin down its exact natural range as it has been cultivated since ancient times and its seeds are easily transported by birds. In the Canary Islands it is considered to have become established in the wild in Gran Canaria, although it is cultivated fairly frequently on other islands.