The mulberry tree impresses with a characterful growth pattern and fragrant fruits. How to plant and care for this woody plant.
Mulberry trees belong to the genus Morus, which is part of the family Moraceae. The well-known species, the recognized number is somewhere between 12 and 15, was originally only found in temperate and subtropical regions of the northern hemisphere, with the exception of Europe. However, the spread of this useful plant can be traced back as far as the ancient Romans and Greeks. As result, you today find representatives of the mulberry tree in practically every region of Europe with a warm viticultural climate. The best known in this country are the white mulberry and the black mulberry. The white mulberry (Morus alba) originates from China and has been used for the rearing of silkworm for over 4500 years. The black mulberry (Morus nigra), originally native to southwestern Asia, has become widespread due to its delicious fruit. And red mulberry (Morus rubra), which is native to North America, is becoming increasingly popular, as the drought-tolerant mulberry tree is one of the trees of the future when it comes to climate change.
Appearance and Growth
The mulberry tree is a deciduous tree with one or multiple trunks, in this country reaching heights between 25 and 50 feet with a crown width of up to 16 foot. Its wood is quite soft and fibrous, and older specimens have noticeable vertical strips. In Asia, the bark is still sometimes peeled and used to make sophisticated Japanese paper. The leaves of the mulberry tree sprout very late and can vary greatly on the same tree. They are usually wide ovate to cordate, but often also two- or three-lobed, similar to fig leaves. The margins are generally coarsely serrated. Most species have pretty yellow fall foliage before they shed their leaves.
Mulberry trees flower in May and June. The ear-shaped inflorescences appear then as catkins or small heads. There are all-male and all-female inflorescences on the same tree, so most species are self-pollinating. The pollen is transported by the wind. The fruit of the mulberry tree is similar to the blackberry, but much longer and almost cylindrical. It is an aggregate fruit which, depending on the species and degree of ripeness, has a white, red, purple, or black color. The fruit of the black and red mulberry tree are considered the tastiest, while the fruit of the white mulberry is described as somewhat bland in comparison. During the ripening period from July to September, the trees should be constantly harvested and the fruit should be consumed or processed quickly, as it is not storable. Birds, squirrels, and insects love mulberries too.
Location and Soil
Mulberry trees are not particularly frost-hardy and are therefore particularly common in regions with mild viticultural climates. However, once well rooted and in a sunny, wind-sheltered location, they are often more robust than expected. The soil should be as deep, loose, and nutrient-rich as possible. A calcareous substrate is also fine. The white mulberry is more tolerant of frosts than black mulberry, but less drought resistant. The red mulberry is similar to the white mulberry in terms of frost resistance, but appreciates moister ground. All mulberry trees are smoke resistant and suitable for urban climates.
All mulberry species should be planted in spring where possible, so that the young woody plants are well rooted by the cold season. It’s important that you loosen the soil in advance and that it drains well. Heavy soils must be provided with drainage!
As trees with a so-called heart root system, mulberry trees reach deep layers of soil and are therefore undemanding in terms of water. All species enjoy a bit of compost in spring. This can be lightly raked into the topsoil in the area around the tree base.
Mulberry trees tolerate pruning well and can also be grown as hedges or as an espalier. The best time for any pruning is early spring. The cutting point exudes a white milky sap, which seals the wounds relatively quickly.
In the first few years in particular, mulberry trees should be protected against frost with a thick layer of leaf mulch followed by brushwood. You can also wrap the trunk of younger specimens using jute fabric or a reed mat to protect the bark against frost crack.
Mulberry trees develop a characterful growth pattern over time, resulting in beautiful trees for home gardens. They can also be grown as fruit trees, espalier trees, or hedges. Its broad, densely foliated crown is a good source of shade, but please bear in mind that the falling fruit can stain floors and garden furniture.
Important Species and Varieties
The ‘Pendula’ is a cultivar of the white mulberry (Morus alba) that amazes with its weeping form. Its branches have dense foliage and drape right to the ground. ‘Pyramidalis’, on the other hand, has a columnar growth habit and reaches an impressive height of 50 foot. Its fruit is white, just like the mother tree. ‘Nana’ is slow-growing with a spherical shape. Morus alba ‘Laciniata’ develops a fascinating growth pattern with zigzagging branches and deeply lobed leaves. As the name suggests, the breed ‘Geraldi Dwarf’ stays quite small. It grows to a maximum height of 6.5 foot and bears plenty of fruit. This variety is ideal for pots and containers! The variety ‘Illinois Everbearing’ is the result of a cross between Morus alba and Morus rubra, characterized by its frost-hardiness and delicious fruit. It grows to a height of around 16 foot. ‘Collier’ originates from France and has large black fruit with a distinctive aroma.
‘Mathildes Traum’ is a cultivar of Morus nigra with strong growth and juicy fruit. It is said to be a descendant of the oldest mulberry tree in Germany. The British variety Morus nigra ‘Chelsea’ has been around since the beginning of the 17th century. ‘Kaester’ has its origins in Los Angeles and is characterized by its very large, sweet fruit.
Vegetative propagation methods are the most promising, such as propagating from cuttings, which are best taken in summer, or using hardwood cuttings which are obtained in fall. Propagation by layering is also possible in fall. Sowing from seed only works if the seeds have had a long period of cold stratification. You’ll have to wait a long time for these specimens to produce their first fruit. You can obtain offspring from the fruit varieties of the mulberry tree by grafting on a Morus alba base.
Diseases and Pests
Young mulberry trees are very popular with caterpillars, slugs, and snails. You should keep an eye out for this during the first three years in particular, but specimens are very robust and resilient once they are well established. Mulberry leaves are sometimes affected by mildew in adverse weather conditions, but this does not cause any serious damage.