Mulberry

Description

Mulberry is the name given to several species of deciduous shrub or tree in the genus Morus (family Moraceae) which are grown for their edible fruits. The genus includes white mulberry (Morus alba) and red mulberry (Morus rubra). Mulberries are small to medium sized shrubs or trees with a thick tan-gray ridged trunk and light green leaves which vary in shape depending on variety. Leaves are arranged alternately and are lobed or unlobed, cordate (heart-shaped), dentate (toothed) and acuminate (tapering). The trees produce small green-yellow flowers in dense spikes and an oval aggregate fruit made up of individual drupelets. The fruit can be white, pink or purple to purple-black in color and contains numerous brown seeds. Mulberry can reach a height of 15 m (49 ft) and are quite short lived, with an economic lifespan of around 15 years. Mulberry is believed to originate from China.


Uses

Mulberries can be eaten fresh or used as fillings for tarts and pies. The fruit may also be used to make jams and jellies. They have been traditionally planted as a food source for silk worms.


Propagation


Basic requirements
Mulberry trees should be grown in sunny locations, preferably in a deep soil. Mulberries are reasonably tolerant of drought, particularly white mulberry and can be grown successfully in poor soil. Mulberry will grow well in a variety of soils but optimum growth will be achieved when planted in a deep well draining loam with a slightly acidic pH of between 5.5 and 6.5. Fruit yields are increased when trees are positioned in full sun. Mulberry trees are cold hardy, although the specific temperature at which they will be damaged varies by variety. Some white mulberries can withstand temperatures of -32°C (-25°F).

Propagation
Mulberry trees can be propagated from seeds, cuttings or by grafting. Seeds should be collected from ripe fruits and removed by macerating the fruit in a water bath. Seeds which sink to the bottom of the bath are viable and can be planted immediately or dried and cold stored for planting later. Trees grown from seed can take 10 years or more to produce fruit. Cuttings can be taken during regular pruning of the tree. Branches should be 22 to 30 cm (8.6–11.8 in) in length and possess a minimum of three buds. Cuttings should be planted immediately. Grafted plants produce stronger root systems than trees produced by any other method of propagation. Grafting is usually achieved by budding in the Spring.

Planting
In the case of mulberry bushes, seedling are transplanted when they have reached 10–15 cm (4–6 in) in height. Seedlings for mulberry trees should be allowed to grow larger, usually at least 1 m (3.3 ft) in height and are trained prior to planting. Mulberry trees do not need to cross pollinate but if growing more than one tree they should be spaced 1.6 m (5.2 ft) apart.

General care and maintenance
Although established trees are relatively tolerant of drought, mulberries should be provided with additional irrigation during dry periods. The trees require little fertilization and a single annual application of a balanced fertilizer is usually sufficient to meet the growing requirement of the trees. Once trained, little pruning of the trees is required. Dead and damaged wood should be removed at the end of the growing season.

Harvesting
Mulberry fruit is usually ready for harvest in late Spring. The fruits are usually harvested by hand either by picking them from the tree directly, or by shaking the branches.


References

Duke, J. A. (1983) Handbook of Energy Crops. unpublished. Available at: http://www.hort.purdue.edu/newcrop/du.... [Accessed 23 February 15]. Free to access.




Common Pests and Diseases

Bacterial blight
Pseudomonas syringae

Symptoms
Small black, angular spots in leaves; large brown spots on leaves, flowers and/or fruits
Cause
Bacteria
Comments
Disease emergence favored by poor air circulation around branches and wet foliage
Management
Branches exhibiting dieback and severe blighting should be pruned out of the canopy; avoid overhead irrigation; if cankers appear on the trunk of the tree then it is likely it will die and it should be removed

Armillaria root rot
Armillaria mellea

Symptoms
Small, discolored leaves which drop from tree prematurely; death of branches; death of entire tree; may be small mushrooms growing in clusters at base of tree
Cause
Fungi
Comments
Fungus survives in dead and decaying wood of infested tree stumps; disease spreads when mycelium colonizes roots of tree
Management
Control of Armillaria root rot once present is extremely difficult; great care should be taken to only plant disease-free planting material; trees should not be planted in recently cleared areas known to have been infested with Armillaria previously; diseased trees, including stumps, should be dug up and removed from orchards; avoid stressing trees by providing adequate irrigation, fertilization and insect control; applications of fungicides is not recommended on infected trees; trees may die within one to several years depending on the severity of the infection