Morus

( MOR - uss )

At-A-Glance Information

This genus of deciduous trees needs full sun and regular water to perform and fruit well. Species that produce berries will attract hungry birds to your garden. These plants are commonly referred to as Mulberry, and their fruit is said to taste like something in between a fig and a blackberry. These plants are native to many temperate regions around the world, and are fast-growing. Take care when planting these trees in your landscape, as the large amounts of pollen produced by male specimens can cause health hazards for those with asthma or breathing issues. Also, all parts of these plants are toxic (except for the edible ripe berries).

morus Species and Varietals

The genus Morus includes 19 species and is in the plant family Moraceae. The best growing zones for Morus trees vary depending on the species. For more information, see the descriptions below. To find your zone, click here: Zone Map.

Morus alba (White Mulberry, Silkworm Mulberry, Common Mulberry)
This species grows well in zones 2-24, H1 and H2 and is native to China and India. They are commercially grown, not for their fruits but for feeding silkworms for the silk-production industry. A fast growing tree, it can reach 30-50 feet tall (though it is usually seen much smaller), and forms a formidable root system, especially those on the surface (making it difficult to garden under). Flowers are inconspicuous, and fruit is white, pink, and purple with a sweet but somewhat underwhelming taste. Berries will stain paved surfaces; take care not to plant these over patios. Varieties include 'Pendula' (a weeping variety that is low-growing), 'Chaparral' (another weeping selection), 'Fan-San', 'Fruitless', 'Kingan', 'and Stribling'.

Morus australis 'Unryu' (Morus bombycis 'Unryu', Morus alba 'Unryu') (Contorted Mulberry)
This species is best in zones 3-24 and is native to eastern Asia. It reaches 25 feet tall and wide, with contorted branches that are beautiful and add interest to dried arrangements. Branches can be cut freely with no harm to the tree due to its fast growth. Leaves are dark green.

Morus cathayana (Hua Sang)
These deciduous trees are native to China, Japan, and Korea and are usually found growing in secondary forests and scrublands. This species reaches about 50 feet tall at maturity, and produces flowers from May through June. Berries are edible and leaves are commonly made into tea.

​Did you know? Silkworms love Mulberry trees.
Mulberry leaves, particularly those on White Mulberry (Morus alba) are the sole food source of the silkworm (Bombyx mori), the cocoon of which is used to make silk. In Ancient Greece through colonial Virginia, these trees were cultivated in order to make silk.

Morus celtidifolia (Texas Mulberry)
Native to South America, Central America, and the southwestern United States, this species forms a shrub or tree to 25 feet tall, and has relatively smaller leaves than other species in the genus. 

Morus indica
This species is native to temperate and sub-tropical regions of the Himalayan mountain range. It is cultivated in India, China, Japan, and East Africa. It takes the form of a shrub or small tree, reaching between 33 and 49 feet tall when mature. Bark is light grey-brown, and leaves are dark green with pale undersides. Fruit is dark purple to black in color when fully ripe.

Morus macroura (King White Mulberry, Shahtoot Mulberry, Tibetan Mulberry, Long Mulberry)
These plants are native to Tibet, the Himalayas, Indonesia, and rainforested areas in Indochina. They form medium-sized trees with spreading canopies that take on a weeping habit when mature. Ripe fruits are pink, white, or red, and are honey-sweet.

​Morus nigra (Black Mulberry, Persian Mulberry)
Best in zones 4-24, H1 and H2, this native of western Asia reaches 30 feet tall and 35 feet wide with a short trunk and spreading head. Fruit is large, black to red and juicy. This species needs regular water to perform and fruit well. Varieties include 'Oscar', 'Wellington', and 'Black Beauty'. This species does well in rich soil.

Morus rubra (Red Mulberry)
This species of Mulberry is native to eastern and central areas of the North American continent, and is considered an endangered species in Canada. Fruits emerge pale green and ripen to red or dark purple. 

Morus serrata (Himalayan Mulberry)
These small trees reach about 50 feet tall when mature, and are sometimes considered to be a subspecies of either White or Black Mulberry. Fruits are edible and red when ripe. Leaves are densely hairy on the undersides. This species is native to mountainous regions of southwestern China. 

Caring for and pruning Morus Trees

Choose a sunny spot in the landscape to plant a Mulberry tree. These trees will thrive in full sun exposure, requiring between 6 and 8 hours of direct sun each day to flower and fruit well. If planting multiple trees or planting trees close to other landscape plants, make sure to leave at least 15 to 25 feet of space (depending on the variety) to allow for full canopy development. They can tolerate a wide variety of soil types, but grow best in fertile, loamy soils that are well-draining. Mulberry trees prefer soil to be neutral to slightly acidic (with a pH of between 5.5 and 6.5). If local soils are clayey, compacted, or otherwise do not drain well, make sure to amend the planting area with plenty of organic matter and/or sand to improve structure and drainage ability before installing trees. Apply a thick layer of mulch around the base of trees and shrubs, ensuring that it stays a few inches away from the trunk of the tree. This will help to suppress weed growth, increase soil moisture retention, and help to regulate soil temperatures. Water newly planted trees regularly, keeping the soil consistently moist but not soggy for the first 2 years after planting. This will help trees to establish a strong, deep root system. At maturity, these trees are fairly drought-tolerant, and can get by on precipitation alone for many months of the year. Water deeply during prolonged dry spells, but avoid overwatering, as these trees do not do well with wet feet.

Pruning Mulberry trees should be completed in late winter to early springtime to shape the tree and remove any dead, damaged, diseased, or crossing branches. Proper pruning of these fruiting trees can enhance air circulation, reduce disease risk, and help to maintain a manageable size for harvesting. Apply a dressing with an organic compost each year in early springtime; this should be sufficient to support the growth and flowering for the year. If trees seem to be struggling, or they are not producing well, they may benefit from a feeding with a balanced, slow-release fertilizer (such as a 10-10-10) applied in early springtime. Avoid over-fertilizing these trees, especially with nitrogen-heavy fertilizers, as this can lead to lush foliage growth at the expense of flowering and subsequent fruit production.

Harvesting Mulberries
Harvesting these delicious fruits is very simple. They are typically ripe in late spring to early summertime, though this depends a bit on the variety, as well as the climate the trees are grown in. To harvest, fruits can be picked by hand off of the tree, or the tree can be shaken to release them (with a tarp laid underneath the tree for easy collection). After harvesting, berries can be stored unwashed in a covered container in the refrigerator for up to two days. If freezing them, wash them off, pat them dry, and then place in a single layer and freeze for two hours (or until they are completely solid). Next, place them in a container. They can then be stored for several months in the freezer. Fresh berries are typically eaten off the tree, used in pies, tarts, or wines, and can also be a clever topping for ice cream, yogurt, and breakfast cereals.

Propagation

Morus can be propagated either by using cuttings or from seed. Mulberries can be grown from seed, and this is often advised, as seedling-grown trees are generally of better shape and health. Mulberry trees grown from seed can take up to ten years to bear fruit. However, Mulberries are most often planted from large cuttings, which root readily. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your Mulberry tree, follow the instructions below:

Propagating Morus by Cutting
  1. Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand.
  2. In spring or early summertime, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 6-10 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
  3. Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots.
  4. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new shrub.

Propagating Morus by Seed
  1. Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows.
  2. Harvest your seeds. They can be taken from freshly picked or fallen fruit, which is typically ready for harvesting around summertime. Gather fruits and either cut them open or smash them against a sieve and rinse seeds until they are clean. Next, place seeds in a bowl of water for between 24 and 48 hours, changing the water at the 24 hour mark.
  3. Seeds will need to be cold-stratified; to do so, place them in a plastic bag or other sealable container filled with moistened peat moss or sand. Place the container in the refrigerator and leave it for about 90 days' time. Remove the seeds and then take them out to work with them.
  4. Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 7-14 days from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
  5. Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.​​

Problems and Pests

Mulberry trees (especially Morus alba) although beautiful and productive, have the potential to be invasive. They are considered to be especially prolific in the mid-west and eastern United States, where it readily spreads and displaces native species in disturbed areas like fields, roadsides, and edges of forest land. It is against the law to install these plants in Illinois, Kentucky, and Tennessee. In addition to being invasive, these plants can suffer from the following pests and diseases:
  • Bacterial Blight
  • Powdery Mildew
  • Popcorn Disease
  • Witches Broom
  • Leaf Spot
  • Canker
  • Mushroom Root Rot
  • Cotton Root Rot
  • Root Knot Nematodes
  • Summer Scorch
For more information on these issues, consult the following pages:
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Gallery

Despite their similar appearance, Mulberries are not closely related to Raspberries or Blackberries (which are in the Rosaceae plant family).
These trees can make great garden ornamentals in addition to producing delicious fruits.
Weeping Mulberry in a formal garden landscape.
These trees have gorgeous, gnarled trunks when mature.
Berries produced by these plants are delicious, and commonly used for preserves and in various dishes.
These trees can have a tendency to lean and produce decumbent branches.

Videos

Learn about dwarf varieties of Mulberry tree.
All about Mulberry fruits.
Learn about the invasive potential of White Mulberry trees.
All about White Mulberry.

Resources

How to Grow Mulberries
White Mulberry (Morus alba) - Invasive.org
Wikipedia: Morus (plant)
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Pages 445 - 446, Morus
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