The Pamphlet Collection of Sir Robert Stout: Volume 84
The best known varieties of the mulberry tree (Morus) are: Morus rubra, red mulberry; Morus nigra, black mulberry; Morus multicaulis, Philippine mulberry; Morus alba, white mulberry.page 4
The red mulberry, so called on account of its fruit, which is of dark red colour, of pleasant, slightly acid taste, is totally unfit for silkworm food. As a rule the worms will not touch its leaves.
The black mulberry is planted for the sake of its fruit, which is of black colour, and has a pleasant taste. The leaves of this variety should only he given in case the food from the white mulberry falls short. The worms have great difficulty in eating the leaves, on account of their being prickly. The worms therefore cannot absorb a sufficient quantity of food, they starve, dwindle, and die, or produce a very poor quality of silk. It is not advisable to use the black mulberry at all for silkworm food.
The multicaulis is chiefly used in Asia and Japan, and—although perhaps not so suited as other varieties, being less rich in nutritive elements—it will do very well for silkworm food. It is a shrub, very prolific, and can be easily and quickly propagated by cuttings and layers.
The white mulberry is the traditional food plant of the silkworm. There are a great many varieties : the best known are Morus Moretti and Morus alba rosea (rose-leaved, or Cevennes). The leaves feel soft, smooth, and glossy. The fruit is of whitish colour and unpleasant taste. The wood is yellowish white, and becomes very hard when the tree gets older. The white mulberry often attains very old age, and will grow over 50ft. high. It is easily propagated from the seed, layers, or cuttings, and this last method is perhaps the quickest and most economical of planting to secure a stock. I am informed, however, by nurserymen that it requires a great deal of time and trouble to propagate the alba rosea from cuttings.