Fruitless Mulberry Tips

The fruitless mulberry tree (Morus alba) is a male tree that grows from 20 to 60 feet in height. A common street tree in urban areas, it produces copious amounts of pollen, carried on the wind, that causes allergies in sensitive individuals. In the residential landscape, fruitless mulberries are grown for their ability to provide shade in the summer. It's a deciduous tree, and somewhat drought-tolerant in maturity.

Features

The mulberry is a host tree for the silkworm. At one time, these trees were grown to encourage the worm in silk production. Silkworm farming didn't catch on, and the mulberry fruit, due to its short shelf-life, isn't viable as a commercial crop. The tree hence became an ornamental, with the fruitless varieties in most demand. Fruitless mulberries are male trees; they include varieties such as Urban and Kingan. There is also a weeping variety -- Chaparral -- that adds a bit of grace to the landscape.

Cultivation

Fruitless mulberry trees are not demanding when mature. Newly-planted, young trees, however, require a bit of extra care. Stake the new mulberry tree to protect it from breakage in high winds. The tree also requires annual pruning in the winter, before buds appear, to remove branches on the bottom of the tree. Fortunately, the tree tolerates heavy pruning, so shorten branches as needed to maintain the shape you desire.

Propagation

Fruitless mulberry trees may be propagated by cuttings or seed. Softwood cuttings, taken in June or July, root easiest. Dip the cutting in rooting hormone and plant it in sand, and you'll have a rooted cutting in three weeks. Fresh seed readily germinates when stratified -- planted in sand and refrigerated -- for three months. Give the seedlings shade in the afternoon for the first three weeks after germination.

Considerations

Although the fruitless mulberry is prized for its resistance to root rot and verticillium wilt, it is highly attractive to a number of pests. Some common garden pests to be on the lookout for include spider mites and whiteflies. These can be managed with miticides and insecticides. Borer beetles are a bit more challenging to manage; use specific insecticides labeled for borers. Consult your cooperative extension office for what to use in your region.

References

• University of California Cooperative Extension: Fruitless Mulberry Tree
• "The Reference Manual of Woody Plant Propagation": Michael A. Dirr and Charles W. Heuser, Jr.
• Urban Forest Ecosystems Institute: Fruitless Mulberry