How to Grow Mulberry Trees

Close up of ripe mulberries and mulberry leaves.

 Getty Images

Along some East Coast city streets, you can find purple-stained sidewalks and cars splotched with crushed berries underneath berry-laden shade trees. When you walk along a wooded lot and spot a mulberry tree, most likely the tree you are observing isn't a native Red Mulberry, but a White Mulberry - or a hybrid of the two.

For years these trees were the bane of many gardener’s existences. The messy, delicious fruit causes quite a mess and helps the weedy spread of the Morus alba. This has cemented the tree on the do not plant and invasive list in numerous states, and gives this species a bad reputation, and rightfully so. The genetic pollution caused by White Mulberry in native Mulberry populations has created worries that Red Mulberry, Morus rubra will eventually go extinct.

The White Mulberry was introduced to North America by the English prior to the American Revolution in an effort to establish a silkworm industry in young America's burgeoning textile industry.

Morus alba is the silkworm's preferred food and the colonies had land to spare to grow the caterpillar's feast. Unfortunately, this grand scheme failed, and the White Mulberry population went rampant due to its ease of germination and spread. It is a favorite food source to birds and mammals and the tree also self-distributes its pollen by rapid plant movement.  

Aided by the wind, the tree has a vast germination range. The stamens eject the pollen like springboards at speeds of 380 mph. In more recent years sterile cultivars have been developed for the nursery trade but the damage may be too late.

It's not just the White Mulberry that can be found in North America, there are five different Mulberry species that grow in this area.

Fun Fact!

The White Mulberry has the fastest known movement of any plant on earth. It launches its pollen out at half the speed of sound by springing its stamen like a catapult in 25 millionths of a second!

Botanical Name Morus spp.
Common Name  Mulberry
Type Tree/Shrub
Size 30-70 Feet
Sun Full Sun for good fruit production. 
Soil Type Best grown in rich, moist, well-drained soils
Soil pH 5.5-7.0
Bloom Time March to April
Flowers Yellowish-green
Zone 4-8
Native Range China (Morus alba) Southwest Asia Morus (Morus nigra) North America (Morus rubra) Southeast Asia (Morus australis)

How to Grow Mulberry Trees

Mulberries are easy to grow even if you have the brownest of thumbs, but they won't be suited to every garden.

Firstly, if you do select a White Mulberry, be sure to pick one of the many seedless cultivars available. Examples include Morus alba 'Chapparal', which is a weeping variety, and Morus alba 'Kingan', a very drought tolerant cultivar suitable for some drier regions.

It is important to know that Mulberry trees will grow fast and send out roots quickly. The most important advice is to plant your tree away from, or take care that your tree is not interfering with, utility, septic or sewage lines. Mulberry roots are notoriously invasive and prolific. With poor or good planning, depending on your outlook is, you should not be surprised to have a wooded area around your mulberry in as little as five to 10 years.

Take the height at maturity of your species into consideration and pick a spot that your tree can be kept relatively free of stress and let it do its job of producing berries and enjoy the many fruits it will offer you.

Light

The Mulberry prefers full sun to part shade.

Soil

Mulberry trees are somewhat adaptable and can deal with clay, loam, and sandy soil with ease if it can maintain sufficient drainage.

Water

Water your tree when initially planted - two to three gallons per week for the first year to help establish a good root system.

Temperature and Humidity

Depending on the species, most Mulberry trees mentioned are cold hardy and can handle freezing temperatures, except for the Texas Mulberry.

Fertilizer

Mature mulberry trees usually thrive with minimal fertilization.

Toxicity of Mulberry Trees

The sap and unripe berries of mulberry trees are mildly toxic.

 Symptoms of Poisoning: 

  • ·        Gastrointestinal issues
  • ·        Hallucinations

Varieties of Mulberry Trees

In North America, the five Mulberries you are most likely to see are:

  • Morus alba: The White Mulberry tree is the most common species found in the country but is considered invasive in many states. It can be easily distinguished from other trees in the genus morus by look for a few key characteristics. The tree has white, sometimes pink to red, blackberry shaped fruits. White Mulberry trees can grow up to 75 feet tall with glossy medium green foliage which is the major difference between White Mulberry and Morus rubra. It is still available in the nursery trade in several cultivars that are ornamental and sterile, which are suitable for planting.
  • Morus rubra: The native Red Mulberry grows to 50 feet tall and is relatively short-lived. Its rough leaves are twice as long as Morus alba and average seven inches long by four wide. The coarse hairy underside is another of the tree's distinguishing features. The fruit is a tight complex cluster, that starts light green then turns to red or dark purple when ripe. Sadly, the Red Mulberry tree is very difficult to find in the nursery trade.
  • Morus nigra: Black Mulberry average 40 feet tall with dark purple almost black berries that are quite large, at over an inch, when ripe. The leaves are about eight inches wide. This variety is available in the nursery trade.
  • Morus australis: Korean Mulberry is a small to medium tree that is 20-30 feet tall at maturity, with light green foliage that is slightly glossed and about five inches long. Fruit color varies from almost white to deep red then turns purple or black when ripe. This tree can be difficult to find in the nursery trade.
  • Morus celtidifolia: Texas Mulberry is native to the Southwest. This tree is shrub-like with a maximum size of about 25 feet. The very small leaves do not get much larger than three inches or so. The edible fruits are red, purple, or nearly black and are quite delicious. The fruits are fantastic for drawing wildlife to your landscape, especially birds.

Harvesting

Image of Mulberry Jam, ripe harvested mulberries, and mulberry leaves.
Getty Images 

Your tree will be ready to produce fruit after three years if all goes well, but when it does be ready to harvest. The key is knowing when because unripe fruit is mildly toxic.

A good time to harvest is between June and August. The darker the fruit, the sweeter the taste. Be warned that mulberries are very tender and will crush easily.

The two methods of picking are handpicking, which can be very tedious, or to place a tarp or old sheet under the tree and give it a good shake. Then collect the unbruised fruit and carefully prepare or freeze the berries if you can keep from eating them before you make any delicious jelly or jam out of them.