Mulberry trees are often overlooked in the realm of fruit-bearing trees, but their delectable mulberry fruit is a hidden gem that shouldn’t be ignored. These trees, which can reach up to 50 feet in height, are known for their glossy, dark green leaves and small, clustered fruit ranging from deep purple to reddish-black. Mulberry fruit is not only a tasty treat for humans and wildlife alike, but it is also packed with natural nutrients. From their historical significance to modern-day uses, mulberry trees have much to offer.
I. Appearance and Characteristics
Morus rubra, commonly known as the red mulberry, is a species of mulberry native to eastern and central North America. It is found from Ontario, Minnesota, and Vermont south to southern Florida, and west as far as southeastern South Dakota, Nebraska, Kansas, and central Texas. There have been reports of isolated populations (very likely naturalized) in New Mexico, Idaho, and British Columbia.
Common in the United States, it is listed as an endangered species in Canada, and is susceptible to hybridization with the invasive white mulberry (M. alba), introduced from Asia.
Red mulberry is a small to medium-sized deciduous tree, growing to 10–15 metres (35–50 feet) tall, rarely 21 m (70 ft), with a trunk up to 50 centimetres (20 inches) in diameter. It can live up to 125 years.
The leaves are alternate, 7–18 cm (2+3⁄4–7 in) long (rarely to 36 cm or 14+1⁄4 in) and 8–12 cm (3+1⁄4–4+3⁄4 in) broad (about twice as big as the white mulberry’s leaves), simple, broadly cordate, with a shallow notch at the base, typically unlobed on mature trees although often with 2–3 lobes, particularly on young trees, and with a finely serrated margin. Unlike the leaves of white mulberry (M. alba) which have a lustrous upper surface, the red mulberry leaf upper surface is noticeably rough, similar in texture to fine sandpaper, and the underside is densely covered with soft hairs. The leaf petiole exudes milky sap when severed. The leaves turn yellow in autumn.
The flowers are relatively inconspicuous: small, yellowish green or reddish green and opening as leaves emerge. Male and female flowers are usually on separate trees although they may occur on the same tree.
The fruit is a compound cluster of several small achenes surrounded by a fleshy calyx, similar in appearance to a blackberry, 2–3 cm (3⁄4–1+1⁄4 in) long. It is initially pale green, ripening to red or dark purple.
The red mulberry develops an extensive root system, containing lateral, horizontal roots that remain within the upper 24 inches of the soil and smaller, vertical roots that go off the lateral roots. This combination gives stability and allows the tree to uptake the nutrients from the soil surface where nutrients are most abundant.
Red mulberry is hardy to subzero temperatures, relatively hardy to drought, pollution, and poor soil, though the white mulberry is hardier.
The berries are widely sought after by birds in spring and early summer in North America; as many as 31 species of birds have been recorded visiting a fruiting tree in Arkansas. The red mulberry is pollinated by the wind.
Mulberry grows in various climatic conditions and can be found in climates between temperate and tropical. Red mulberry plants require a total annual rainfall of 1,000–2,000 mm (39–79 in) and are adapted to altitudes of up to 800 msl. The native environment of red mulberry most often consists of moist forests, thickets on the floodplains, moist hillsides and river valleys. It can tolerate short periods of flooding and can tolerate temperatures as low as −36 °C (−33 °F). Optimal growing temperatures are between 24 and 28 °C (75 and 82 °F). At least 140 frost free days a year are required. Normally, the tree grows in full sun, but growth is also possible in partial shading. Red mulberry is also drought tolerant.
In its native habitat red mulberry grows in mesic hardwood forests in moist soils, although they can be found in many different moist soils. Such soils include inceptisols, alfisols, spodosols and ultisols. The plants prefer deep, well drained soils that range from loamy to clayey and have a high moisture-holding capacity. A soil pH of 5-7 is optimal.
II. How to Grow and Care
Sunlight
The tree will be its showiest and produce the most fruit when placed in full sun. It does tolerate part shade somewhat well but will not produce as proficiently.
Temperature and Humidity
The species is a hardy tree with a range covering most of the United States east of the great plains. The red mulberry does well at a variety of temperatures. Its USDA Hardiness Zones are 3-8.
Watering
Other than when first planted, there is no need to worry about supplemental watering. Initially, it is necessary to water the newly planted tree weekly. A thorough soaking is adequate. A good rule to go by is ten gallons of water for each inch of the trunk diameter. Weekly watering only needs to be maintained for the first year until roots are established.
The red mulberry tree is drought-resistant, but it would be best if you still watered them to keep the soil around them from drying out during a drought. That way good fruit production will be more likely.
Soil
To ensure success, place the red mulberry tree in well-draining conditions that are moist and rich. A loamy soil that is neutral to alkaline is preferred.
Fertilizing
There is no need to fertilize the red mulberry tree. It will do well in most soils, but increasing the yield of berries can be achieved by applying a 10-10-10 slow-release fertilizer every spring.
Pruning
Mulberry trees have rather delicate bark and are prone to “bleeding” if cut during the growing season. So, only prune dead or damaged limbs during winter dormancy. This is also the time to prune your mulberry for guiding its growth toward the desired shape.
Propagation
Mulberry trees can be propagated with branch cuttings. Here’s how:
- Cut an 8-inch long end of a green branch with a 1/2-inch diameter.
- Dip the bottom of the cutting into rooting hormone, and plant about 3 inches deep in a small pot filled with soilless potting mix.
- Water thoroughly, then place the pot in a clear plastic bag to retain warmth and moisture.
- Place the pot in a full shade location for about 4 weeks, until the cutting begins to root. Keep soil moist but not soggy.
- When the cutting has rooted, remove the plastic bag and continue growing in the pot through the summer.
- In the fall, plant your little tree in the ground.
How to Grow from Seed
Red mulberry can be planted from seed and can be sown without stratification (a cold period) in the summer and fall; they can also be planted in the spring after 30 to 90 days of stratification in the refrigerator. The seeds should be planted 8 to 12 inches apart.
Trees will produce fruit in 4 to 10 years.
Overwintering
Red mulberry trees are cold tolerant and do not need special care during the winter.
Pests and Diseases
- Common Pests
Red mulberry trees are generally pest-resistant, hardy trees in their native growing areas. Young trees may be browsed by deer, which can harm growth, but fencing off small trees keeps deer at bay until the trees are large enough to survive on their own.
- Common Problems
The fruit that makes this tree so attractive to some people is also the reason people shy away from using red mulberry in their landscapes. After falling, the crushed fruit is notorious for staining anything in the area under its canopy. In addition, birds love the fruit and deposit their droppings, which are brightly colored around the area. Red Mulberry is a fantastic tree for feeding wildlife, but this species might need to be overlooked if cleanliness matters.
III. Uses and Benefits
- Ornamental uses
Red mulberry has variable leaves that turn a brilliant yellow during the autumn, giving a wonderful vista if planted at the edge of woodlands. The fruit produced by this tree is edible, so it wouldn’t be unusual to grow it at the edge of a kitchen garden. It is also suitable for children’s or pollinator gardens.
- Medicinal uses
Some Native American tribes used an infusion of the bark as a laxative or purgative. Infusions of the root were used to treat weakness and urinary ailments. The sap was applied to the skin to treat ringworm. Choctaw people wove clothing from the inner bark of young M. rubra and similar shoots.
- Culinary uses
The berries are edible and sweet.
Today, mulberries are eaten raw, used in the fillings of pastries, and fermented into wine. They are also used for marmalades, liquors, natural dyes, and cosmetics. The berries are not commercially sold because they have very short “shelf lives” and pack/ship very poorly.
- Other uses
The wood may be dried and used for smoking meats with a flavor that is mild and sweet. It is also used for fence posts because the heartwood is relatively durable. Other uses of the wood include farm implements, cooperage, furniture, interior finish, and caskets.
