Morus nigra, Black mulberry
A spreading deciduous tree with juicy black fruits and leaves which can be used to lower blood sugars and with potential in anti-ageing disorders.
scientific name Morus nigra Mill.
family Moraceae
parts used Leaves and fruits
Description
A deciduous tree with numerous branches eventually growing to 10m tall by 10m wide. Leaves have rough surfaces, often varying in shape; some are multilobed and others not. Flowers appear in May-June as small scaly clusters and ripen into blackberry sized edible fruits from August to September. Trees are either monoecious or dioecious and can change from one to the other. Flowers are wind-pollinated and fruiting generally begins after 15 years of age.
Habitat
Black mulberry is a native shrub of southwest Asia, now widely planted in Europe, Africa and India.
Related plants
There are a number of black mulberry cultivars; the variety ‘Chelsea’, also known as ‘King James’, produces well-flavoured fruit. The red mulberry (M. rubra) is a native of eastern North America, growing up to 20m, and the white mulberry (M. alba) originates in northern, eastern and central Asia. Some mulberry cultivars do not produce fruit but have large leaves.
A fully grown mulberry tree
Cultivation and harvest
Cultivation
Black mulberry is hardy in USDA zone 5 (UK zone 5). After rapid growth when young, it is fairly slow growing. It likes a moist but well-drained soil and appreciates neutral to acid soil. It is resistant to cold but grows best in full sun, can grow in dappled shade, fruiting well in southwestern UK, and can be grown with protection further north. The tree can be grown in various forms as it tolerates pruning well: coppiced, pollarded as a tall standard, as a bush or fan-trained against a wall, or cultivated in a pot. It is not advisable to prune the tree heavily due to an inclination to bleed, so prune while it is dormant.
Pests and diseases
Black mulberry is generally free of pests and diseases, although cankers and dieback can occur. A white powdery coating on the lower leaf surface is a symptom of mildew spread by the pathogens Phyllactinia corylea and Uncinula geniculata.
Seed propagation
Seed-grown trees are said to be stronger. Sow the ripe seed in a cold frame. The seed usually germinates in the first spring, though it sometimes takes another 12 months. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in the cold frame for their first winter. Plant them out in late spring or early summer after the last expected frosts. Cuttings of half-ripe wood, 7-10cm with a heel, can be taken in July/August. Cuttings of mature wood of the current season’s growth, 25-30cm with a heel of two-year-old wood, taken in autumn or early spring are placed in a cold frame. Bury the cuttings to three-quarters of their depth. Older cuttings may also strike. Layering in autumn.
Harvesting
The leaves can be used fresh or dried. Fruits drop as soon as they are ripe and so a grass or protective layer on the ground helps when they are harvested, and they can be frozen.
Black mulberry fruit are delicious
Therapeutic use
Traditional
The black mulberry has similar properties to the white mulberry which has a long history of use in China as a medicine and traditional uses include preventing liver and kidney diseases, joint damage and degenerative diseases of ageing.
Medicinal actions and uses
The leaves are antimicrobial, anti-inflammatory, anti-oxidant, astringent, diaphoretic and hypoglycaemic.1 The leaves are taken internally for colds and influenza. A tincture of the bark is used for toothache, is anthelmintic and purgative. The fruit has laxative and fever-reducing properties. It is used in urinary incontinence, tinnitus, premature greying of hair and constipation in the elderly. A leaf, flower or root decoction can be gargled for sore throat and swollen vocal chords.
Clinical applications and research
Black mulberry has attracted support for use in chronic disease as a nutraceutical especially due to anti-oxidant activity – both fruit and leaf.2 The anti-oxidant effects are relevant to preventing diseases related to ageing. Flavonoids are hepatoprotective and use of the tincture extract of black mulberry leaves may be appropriate where the liver is affected by drugs, however so far most studies have been carried out on animals. Mulberry leaves provide a possible treatment in diabetes due to their hypoglycaemic effects, and the leaves may have fewer side effects than drugs such as metformin which can affect the liver and cardiovascular system.3 Blood sugar reductions have been found in a trial with women with impaired glucose tolerance.4
Sample preparations and dosage
Tincture of mulberry leaf, 1-1.5ml three times daily. Mulberry leaf tea, 1 tsp in a cup of hot water, steep for 10 minutes and drink up to three times per day.
Constituents and commerce
Key constituents
The fruit of black mulberry contains anthocyanins and phenolic acids. The leaves contain sugar-mimicking alkaloids with hypoglycaemic properties that can affect the metabolism and transport of sugars in the body.
Commerce
The main use of mulberry in modern medicine has been for the preparation of a syrup obtained from the ripe fruit used to flavour or colour other medicines.
Safety
Male plants can produce copious pollen.
Other uses
Edible fruit. Animal forage. The leaves are repeat harvested in tropical areas for biomass and silkworm rearing.
1 Barker (2001) section 24.
2 Lim SH and Choi C. (2019) Pharmacological properties of Morus nigra L. (black mulberry) as a promising nutraceutical resource. Nutrients 11: 437; Yang MY, Huang CN, Chan KC, et al. (2011) Mulberry leaf polyphenols possess antiatherogenesis effect via inhibiting LDL oxidation and foam cell formation. J Agric Food Chem 59: 1985-1995.
3 Rodrigues EL, Marcelino G, Silva GT, et al. (2019) Nutraceutical and medicinal potential of the Morus species in metabolic dysfunctions. Int J Mol Sci 20: E301.
4 Hwang S, Li H, Lim S, et al. (2016) Evaluation of a standardized extract from Morus alba against α-glucosidase inhibitory effect and postprandial antihyperglycemic in patients with impaired glucose tolerance: A randomized double-blind clinical trial. Evid Based Complement Altern Med 2016: 8983232.