If you are looking for a large-growing plant that produces an abundance of sweet-tart berries without nasty thorns, then a mulberry tree ticks the box. Depending on the type, fruits up to 1.5 inches long, prized by wildlife and humans, cover the tree in springtime through summer. One mature tree produces enough berries for your family and sharing with friends.
There are three types of mulberry trees cultivated in the U.S. Each has similar growth requirements and habit, with the main difference being fruit size, taste, and tree size.
All mulberries are deciduous and fast-growing and flowers are nondescript catkins that produce the tasty berries. In fact, you might not even notice the catkins until they start developing color as the berry goes through its ripening stage.
Native to the U.S., red mulberry (Morus rubra), also called American mulberry, averages around 40-feet tall and wide at maturity and has a life span of approximately 75 years. The tree is hardy in USDA zones 4 through 9. Of the three cultivated types, red mulberries produce the largest leaves, with toothed, heart-shaped foliage averaging 5-inches long. Flowering occurs in late spring followed by red to deep blue-black fruits about 1-inch long with a sweet and tart flavor. Trees can have both male and female flowers for pollination.
Producing what many consider the best tasting fruits, black mulberries (Morus nigra) are Asian natives and hardy in USDA zones 5 through 9. The self-fertile tree reaches up to 30-feet tall and wide at maturity and if left untrained, typically grows as a large bush. Very long-lived and producing fruits for over a hundred years, the black berries are the largest of the three types growing up to 1.5-inches long with a sweet-tart taste. As with all mulberries, the fruits don't ripen at once and continue ripening over an extended period that can last several months. Foliage resembles the red mulberry but smaller.
An Asian native, white mulberries (Morus alba) have the highest tolerance to cold weather of the three types and are hardy in USDA zones 4 through 9. It is a large tree at maturity, growing over 50-feet tall and wide. White mulberry trees bloom and produce fruits earlier than the other two types, starting the flowering process in early spring. The foliage of this specific mulberry is the primary diet for silkworms used to manufacture silk. This variety is thought by many to be the least tasty of the three types because the berries lack tartness. The fruits are the smallest, with colors ranging from white, pink, blackish, and purple. Foliage is large, glossy green and deeply lobed whereas the foliage on the red and black mulberries has no gloss and is dull green.
Unlike many other types of fruit trees, mulberry trees don't require a lot of fussing to thrive. Once they establish themselves in the landscape, you can almost forget about them and they will quickly achieve their mature size. Keep in mind that the soft berries can create a purple mess, so situate the tree away from walkways and in an out-of-the-way location.
Landscape Location and Use
For the best growth and performance, plant the fruit tree in a location that receives full-sun or partial shade. Consider the tree's mature height and width when selecting a permanent location and give it room to spread, both in width and in height.
Due to the tree's large size, mulberries make great shade trees. They also work well used in native and wildlife gardens, and the tree has a good resistance to wind, making it a useful windbreak.
Mulberry trees tolerate a wide range of soil types as long as they drain well. They even grow well in sandy soils that lack any nutrients. However, if your soil is too sandy and doesn't retain moisture, you can amend the planting site with compost to help retain moisture while the root system establishes itself.
Newly planted mulberry trees require weekly water applications for approximately six to eight weeks after planting while the tree's root system establishes itself. Once established, the tree is tolerant to drought conditions and monthly water applications are sufficient.
Applications of fertilizer aren't required for the mulberry tree to achieve healthy growth. However, an annual application of a general-purpose blend like a 10-10-10 will give the tree a needed boost, especially if the tree suffered damage or seems like it's experiencing stunted growth. Spread the product under the canopy following label directions on amounts, and don't butt the fertilizer against the tree's trunk. Water the fertilizer into the soil after applying.
Mulberry Tree Maintenance
Mature mulberrys are low-maintenance trees that require little care once established and mature and suffer few problems grown in the preferred conditions. They are great choices for lazy gardeners who want a tree they can basically plant and forget.
Unless you are growing the mulberry as a large shrub, the main portion of pruning takes place while the tree is young to create a strong structure. Prune away extra branches to create one main trunk. Trim off branches to create a strong structure for the canopy, leaving five to seven main branches that are open and not crossing. The best time to prune the mulberry is when the tree is in its deciduous state.
Once the mulberry matures, it rarely requires pruning and any cuts are slow to heal as the tree bleeds. However, gardeners may select trimming to control the tree's size, though never prune back more than one-third of the tree's canopy or it might not recover. Trim off any dead or crossing branches any time throughout the year. The pruned branches exude a milky sap that causes an allergic reaction for some people, so wear gloves and a long-sleeved shirt to protect your skin.
Pests and Diseases
Pests or diseases rarely bother mulberry trees. The tree can develop root rot if planted in a site that retains water and doesn't drain well. Therefore, it's important to plant the tree in soil that drains. Whiteflies can be a problem, but rarely require control, which is difficult due to the tree's large size. If the pest infestation is heavy, control by blasting them off the tree with a strong stream of water.
Because the mulberry fruits are soft and easily damaged, harvest the berries with care, trying not to smash them. For this reason, the fresh berries do not have a long shelf-life. Fresh-picked mulberries remain good for two to three days stored in the refrigerator.
Once ripe, mulberries easily fall from the tree and before you know it, you'll have the ripe berries covering the ground underneath the tree. You can harvest the berries by plucking them from the tree one-by-one, remembering the fruit will stain your fingers purple. To gather a large supply at once, spread a tarp or sheet under the tree and shake the branches allowing the fresh berries to land on the tarp.
Locating a Mulberry Tree
In some locations mulberry trees have a tendency to become invasive, so you might not find a tree at standard nurseries. You will have your best chance of locating a tree at native plant nurseries. If that doesn't work, contact your local chapter of the Native Plant Society and they can put you onto a local grower that has mulberry trees in stock. Since the tree grows so fast and can start producing fruit while still young, you will more than likely locate mulberry trees that are around one year-old.
Some mail order plant dealers also sell the tree in its small form and it will arrive while still in its deciduous state. However, the bonus to selecting a tree locally is that you can inspect the tree before purchasing. Look for healthy trees that do not look to have any pest or disease problems and make sure it's not root bound in the container. Root bound plants grown too long in their containers sometimes have growth problems once planted in the ground.
Enjoy Your Bountiful Berries
Mulberry trees not only make handsome specimens that offer shade and fruit, but your local bird and wildlife population will love you as they gobble up the extra and unused berries. Once you harvest your personal bounty of juicy fruits, eat them fresh or use them to make pies, beverages including wine, jams, jellies and desserts.