Mulberry
Morus spp.
Family: Moraceae
The taxonomy of Morus is complex and disputed. Fossils of Morus appear in the Pliocene record of the Netherlands. Over 150 species names have been published, and although differing sources may cite different selections of accepted names, less than 20 are accepted by the vast majority of botanical authorities. Morus classification is even further complicated by widespread hybridization, wherein the hybrids are fertile.
Though the fruits raspberries and blackberries, they are not closely related. Rather they are in the same family as figs!
A Babylonian etiological myth, which Ovid incorporated in his Metamorphoses, attributes the reddish-purple color of the mulberry fruits to the tragic deaths of the lovers Pyramus and Thisbe. Meeting under a mulberry tree (probably the native Morus nigra), Thisbe commits suicide by sword after Pyramus does the same, he having believed, on finding her bloodstained cloak, that she was killed by a lion. Their splashed blood stained the previously white fruit, and the gods forever changed the mulberry's colour to honour their forbidden love.
As with olives, mulberry planting has been restricted in Pima County, the result of the lack of relationship anglos have with this crop which was brought to our region by Spanish colonizers. Mulberries, like olives, were associated with Mexican neighborhoods. Anglos find the trees messy, and lacking a cultural connection to the plants, were fine with having them banned, supposedly because of their airborne pollen production (which isn’t much different than many other wind-pollinated plants like popular oaks, pines, and other landscape plants in the trade).
Luckily, government employees are terrible botanists. The mulberry plants banned in Pima County are of the species Morus rubra, which has seldom been planted in our region. This means that legally, white mulberries (Morus alba), black and Persian mulberries (Morus nigra), Pakistani mulberry (Morus macroura), and native mulberry (Morus microphylla) are all legal.
USES AND PRESERVATION
Mulberries are wonderful eaten fresh. They can be frozen easily for later use. Mulberries are also easily dehydrated for additions to granola or just to snack on individually.
Mulberry syrup is made by cooking down into a simple syrup, adding sugar. Mulberry syrup will last a long time in the fridge or even on a shelf.
Mulberries are used in pies, tarts, wines, cordials, and herbal teas.
Mulberry leaves, particularly those of the white mulberry, are ecologically important as the sole food source of the silkworm (Bombyx mori, named after the mulberry genus Morus), the cocoon of which is used to make silk. The wild silk moth also eats mulberry. Other Lepidoptera larvae—which include the common emerald, lime hawk-moth, sycamore moth, and fall webworm—also eat the plant. Pollarding of mulberry trees (which is a practice that greatly reduces the life span of the tree) is a classical agricultural method used in the production of silk, producing lots of reachable foliage for silk harvest (the long whippy stems were sometimes used afterward for basketmaking).
GROWING
Mulberries are easy to grow in our region. For best fruiting, plant in full sun, perhaps avoiding too much reflective heat. Plant in amended soil. A layer of mulch around the base of plants is beneficial, but avoid burying the base of the plant (the root flare).
Water once or twice a week during the growing season. Back off to about once a month in winter.
Feed in February with a general purpose organic fertilizer.
Most mulberries are shrubs, a few become trees. Avoid pruning, and allow the plant the room it needs to grow. Unless you are in the business of silk production, you do not need to pollard trees.
COMMON MULBERRY VARIETIES IN OUR REGION
Black Mulberry (Morus nigra) Large, shiny fruit similar to Persian. Can be grown as a tree or large shrub. Attractive to birds. Self-fruitful. The black mulberry comes in a dwarf variety that is most commonly available in our region.
Pakistani (Morus macroura) Long (3 inches), firm, red to black, sweet fruit. Non-staining juice. Month-long early summer harvest. Fruit used fresh and for pies, jams and jellies. Large, vigorous, disease-resistant tree. Self-fruitful.
Persian (Morus nigra) Densely foliated tree to 25-30 ft. Large heart-shaped leaves. Large fruit is juicy, dark red to black and good for jam. Self-fruitful.
Texas Mulberry (Morus microphylla) tiny fruits on shrubs that reach up to 30’ tall in riparian zones, but in the low desert are usually smaller shrubs. This is a native plant. Though fruits are usable for syrups they have limited applications for culinary use. Plants are dioecious—you need to have identified males and females available for fruit production.
White (Morus alba) Medium-sized, sweet, white fruit shaped like blackberries. Grows at a moderate rate to 20-60 ft. depending on soil quality and depth. Drought tolerant once established. Grows larger and more rapidly with irrigation. Self-fruitful.