The mulberry has royal associations dating back to Tudor times. The mulberry tree has a spreading habit and becomes crooked and gnarled with time, making an architectural feature. It has attractive leaves and tasty fruit that are rarely found in the shops. Tolerant of a range of soils, mulberries can be grown against walls if space is limited.
Mulberries flourish in soils that are deep, moisture-retentive, but well-drained. Planting at the optimum time and buying trees with healthy roots will help ensure successful establishment.
- Plant mulberries in spring as the soil warms up
- Bare-rooted specimens usually establish well, but if buying a container-grown specimen, check that the roots are not circling
- Try to find a specimen that is part-trained. This will create a well-formed tree more quickly
- Allow 5-10m (16-33ft) in diameter for the tree to develop its spreading habit
- Improve the soil over the planting area before digging the planting pit
- Staking mulberry trees in the early years will prevent windrock, leading to good root development
- Ensure that the young tree does not dry out in the first few seasons to aid establishment
- Mulberries can be grown in containers for 10-15 years if watered carefully in summer
- Use a good loam-based compost such as John Innes No 2
- Before growth re-starts in spring, pot the tree on each year into a slightly larger container
- In late winter, apply a general purpose fertiliser such as Growmore or fish, blood and bone at a rate of 70g per sq m (2oz per sq yd)
- In spring, apply a mulch of organic matter such as well-rotted manure
- Fruiting may not begin until eight or nine years after planting
- The picking season is over three weeks in August and September
- Gather the fruit by shaking branches over a sheet spread on the ground
- Wear gloves if you want to avoid the fruit staining your hands
Pruning and training
Any necessary formative training is most likely to have been have been carried out on the nursery before purchase
- In the open garden, grow and train formative pruning as a standard or half-standard tree.
- Prune mulberries when they are fully dormant; about a month after leaf fall. This should prevent sap bleeding from the cut surfaces
- Each winter remove badly placed shoots that interfere with the shape of the tree. Remove any that appear on the trunk below the framework and those that are dead, broken, crossing or over-crowded
- It is always best to support low-hanging branches by driving a forked stake into the ground and resting the branch on this, cushioned with sacking. Avoid remedial pruning since mulberries bleed sap from the cuts
Training and pruning a mulberry as an espalier
- Growing a mulberry as an espalier is more unusual but ideal way to use a south-, south west- or west–facing wall. Plants grown in this way will need a space 4.5m (15ft) wide and 2.4m (8ft) high
- Buy a young tree of around two or three years old and train the plant as for an apple and pear espaliers
- Once established, prune lateral shoots, (side shoots) that arise from branches and stem back to three or four leaves to produce short fruiting spurs. This needs to be carried out in late summer, just as growth is slowing down
Pruning as a bush
- In winter, cut down the leader to about 1.35-1.7 (4½-5½ft) just above some strong side-shoots. Use these to develop a framework of 8-10 branches, as for bush apples
- Minimal pruning will then be necessary
Mulberries can be increased in a number of ways;
Hardwood cuttings are a reliable way of propagating mulberries and are best taken in late autumn or early spring.
- Cut well-ripened young shoots 30-60cm long (1-2ft). Treat with hormone rooting powder
- Insert cuttings into soil in a cold frame to a depth of 15-20cm (6-8in)
- The following autumn plant the young plants out and grow on for two years before planting in final position
Morus roots well from larger pieces of wood up to 10cm (4in) thick. In winter, plant two- to four-year-old ‘truncheons’ straight into the ground in their permanent positions.
Propagation from seed
Mulberries can be grown from seed, but need a period of cold to start germination. See growing from seed for more information and Plants for a Future.
There are a number of black mulberries to choose from;
Morus nigra AGM: the species is highly recommended, is widely available and an excellent performer in terms of fruit production and as an ornamental tree.
Morus nigra ‘Chelsea’ (syn. ‘King James’): a cultivar of great historical interest, originating in the Chelsea Physic Garden, London. Fruit is especially large and succulent with an intense, rich flavour. It can be eaten fresh, in preserves or made into wine.
Morus nigra ‘Wellington’: this cultivar crops heavily with medium sized fruit 3cm (1¼in) long and a good flavour
The white mulberry (Morus alba) is also grown for its fruits but is considered to have fruit of inferior quality to the black mulberry (M. nigra).
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Mulberries are not overly prone to problems but watch for the following;
- Mulberries can suffer from a bacterial leaf spot which can cause dieback. Cut out any affected branches in autumn and burn them
- Protection from birds may be necessary by using netting on smaller trees
- As trees mature, mulberries have a tendency to lean or suffer from split limbs. To avoid splits or having to make large pruning cuts, prop low-lying branches before their weight causes them to break