White mulberry is the most common type of mulberry tree that grows in North America. White mulberry can be identified from its blackberry-shaped fruit that starts as white and turns purplish red as the season progresses. White mulberry trees tend to grow and thrive in any conditions within their hardiness growing zone. Continue reading for more information on white mulberry care.
I. Appearance and Characteristics
Morus alba, known as white mulberry, common mulberry and silkworm mulberry, is fast-growing. It is generally a short-lived tree with a lifespan comparable to that of humans, although there are some specimens known to be more than 250 years old. The species is native to China and India and is widely cultivated and naturalized elsewhere (including the United States, Mexico, Australia, Kyrgyzstan, Argentina, Turkey, Iran, and many others).
The white mulberry is widely cultivated to feed the silkworms employed in the commercial production of silk. It is also notable for the rapid release of its pollen, which is launched at greater than half the speed of sound. Its berries are edible when ripe.
On young, vigorous shoots, the leaves may be up to 30 cm (12 in) long, and deeply and intricately lobed, with the lobes rounded. On older trees, the leaves are generally 5–15 cm (2.0–5.9 in) long, unlobed, cordate at the base and rounded to acuminate at the tip, and serrated on the margins. Generally, the trees are deciduous in temperate regions, but trees grown in tropical regions may be evergreen.
The flowers are single-sex catkins; male catkins are 2–3.5 cm (0.8–1.4 in) long, and female catkins 1–2 cm (0.4–0.8 in) long. Male and female flowers are usually found on separate trees although they may occur on the same tree. The fruit is 1–1.5 cm (0.4–0.6 in) long. In the wild it is deep purple, but in many cultivated plants it varies from white to pink. It is sweet but bland, unlike the more intense flavor of the red mulberry and black mulberry. The seeds are widely dispersed in the droppings of birds that eat the fruit.
The white mulberry is scientifically notable for the rapid plant movement involved in pollen release from its catkins. The stamens act as catapults, releasing stored elastic energy in just 25 μs. The resulting movement is approximately 380 miles per hour (610 km/h), about half the speed of sound, making it the fastest known movement in the plant kingdom.
II. How to Grow and Care
Sunlight
To account for their broad and wild-growing root systems, all the species of Mulberry trees demand full light and must be spaced at least 15 feet apart. While the white and red types require 4 hours of direct, unfiltered sunshine in most cases, they can flourish in partial shade in some growing circumstances. So treating them as an outdoor plant will surely get them their maximum growth.
Because your tree will most likely be one of the taller species in your landscape once it reaches maturity, you shouldn’t be concerned about light when deciding where to plant it!
Temperature and Humidity
The hardiness of the white mulberry is not an issue. It stands up well to droughts and cold weather in its habitable zone, USDA 4 through 8, quite well, but the main weather concern regarding the species comes from its weak wood. While it stands up to the weather quite well, its wood just does not have the strength to compete with strong winds or heavy build-ups of ice or snow on weak branches.
Watering
Water newly planted White mulberry trees regularly to encourage the development of a robust root system. They should be able to get their water needs met from the environment once they’ve been established. You must guarantee that they receive at least 1 inch of water deep into the soil every week during dry months.
If the roots are allowed to dry out, the fruit will fall to the ground before ripening.
Mulberry trees are drought tolerant once established, yet extended dry weather might cause a reduction in fruiting or early berry dropping (before they’re fully mature).
Soil
It’s rare to find a plant or tree like the white mulberry that grows so well in any soil condition. In urban areas, they are often known for growing in empty lots riddled with construction debris. The only condition it will not survive in is soil that is saturated consistently. Provide a cultivar with rich loamy soil that is well-draining with a neutral pH.
Fertilizing
During the first year of growth, mulberry trees should not be fertilized. It may be feasible to wait until after the second year of growth to fertilize them, depending on your soil test results.
You can use a balanced, slow-release fertilizer with an NPK ratio of 10-10-10 in late winter or early spring, just before new growth begins, once they are established. For every inch of trunk diameter, apply 1 pound of fertilizer.
If your mature tree is not displaying evidence of recent growth but is generally healthy and unaffected by stress, you may only need to apply nitrogen to meet its nutrient requirements.
Pruning
The chore of pruning your white mulberry will be done mainly for maintaining the tree to ensure it does not break under the stresses of winter weather or high winds. This should be done by looking for weak, intersecting branches with deep crotches, damaged or dying branches, and wood that is growing inwards towards the leader. This task should be done during the winter to avoid unsightly bleeding that occurs when the genus is pruned, which can in turn allow some diseases to infect the tree.
When pruning and trimming straight species, your second task will be the removal of any newly sprouted seedlings or saplings in the vicinity. Carefully remove from the root all plant material and dispose of the waste properly according to local ordinances.
Propagation
It is very easy to propagate any mulberry tree, including white mulberry and its cultivars, using a cutting. Cuttings are preferred over the more difficult and hit-or-miss method of growing a mulberry tree seedling from seeds. You may even be able to simply take a 6- to 8-inch-cutting of a white mulberry tree any time of year and stick it in the ground and it will take root right there. Or, take these steps:
- With a sterilized cutting tool, take a 6- to 8-inch cutting (virtually any time of the year) and remove all the leaves except at the top.
- Stick the bottom of the cutting in the rooting hormone.
- Fill a pot with a well-draining soilless potting mixture, such as peat moss, vermiculite, and perlite in equal amounts.
- Place the pot in a shaded area for up to 60 days to let the roots take hold.
- Water to keep moist but not soggy.
- Before placing the cutting in a permanent home, gradually expose it to the sunlight over a couple of weeks.
Potting and Repotting
White mulberry trees, most specifically dwarf types, can be ideal potted trees. Choose a large plastic container at least 12 inches wide and deep to start. Plastic is best because it will be lightweight and moveable. Make sure the pot has adequate drainage holes. Watch for roots growing out of the bottom of the pot. That means it’s time to repot to a large container so the roots don’t start aggressively searching for water outside of the pot. Use a good mix of potting soil and perlite. Place the pot in full sunlight (though it can tolerate shade) and water well.
Pests and Diseases
Unfortunately, you’ll have very few bug problems in your tree. You might see mites or mealybugs, but a strong stream of water from your garden hose will kill them. The other good news is that these bugs won’t do much damage to older trees since they’re sturdy enough to handle them, which is a good thing because treating a giant 50-foot tree is no easy task.
You can also use a horticultural oil like neem oil if you discover signs of an infection on a more fragile young sapling.
Even with the best of care, a mulberry can have popcorn disease, a fungal infection. This disease is named for the fact that it causes the fruit to expand and resemble popcorn. Infected berries will fall off the tree and should be removed as soon as possible to prevent the illness from spreading and affecting the harvest the following year.
You can treat the entire tree with a copper-based fungicide in the hopes of saving the fruit that isn’t diseased.
III. Types of White Mulberry Trees
Consider planting a white mulberry tree cultivar that is sterile and bears no fruit (male) to avoid the tree from becoming weedy or messy from fruit drop. Only the female trees produce fruit. Or you can check out another species of mulberry tree native to your area. Here are a few fruitless white mulberry tree cultivars:
- Morus alba ‘Chaparral’ is a fruitless dwarf cultivar with a maximum height of 8 feet and deeply weeping foliage.
- Morus alba ‘Pendula’ is another fruitless dwarf and a weeping cultivar that grows a bit taller to 13 feet.
- Morus alba ‘Stribling’, ‘Urban’, and ‘Kingan’ are all fruitless male varieties with broad irregular leaves with medium green foliage.
- Morus alba ‘Hampton’ is a fruitless cultivar that grows to 50 feet.
IV. Uses and Benefits
- Culinary uses
The leaves are prepared as tea in Korea. The fruit are also eaten, often dried or made into wine.
- Ornamental uses
For landscaping, a fruitless mulberry was developed from a clone for use in the production of silk in the U.S. The industry never materialized, but the mulberry variety is now used as an ornamental tree where shade is desired without the fruit.
White mulberry, Morus alba ‘Pendula’, is used as an ornamental plant. It was planted at several grand stations built along the Lackawanna Railroad in New Jersey during the late 1800s and early 1900s. The species is a lawn tree across the desert cities of the southwestern United States, prized for its shade and also for its cylindrical berry clusters composed of sweet, purplish-white fruits. The plant’s pollen is problematic in some cities where it has been blamed for an increase in hay fever.
- Other uses
White mulberry leaves are the preferred feedstock for silkworms, and are also cut for food for livestock (cattle, goats, etc.) in areas where dry seasons restrict the availability of ground vegetation.
