This article was originally published on March 19, 2000 as a bi-monthly news column for the Vero Beach Press Journal.
Date of release: March 15, 2000
Daniel F. Culbert, County Extension Agent
GOING ROUND THE MULBERRY TREE
With the spring flushes of new leaves on our trees, office visitors often bring branches to us for identification. This week two office visitors sent in twigs from the same plant, and another mailed in diseased leaves for us to identify. When a trend like that occurs, itís time to break out the references and describe the attributes and shortcomings on one of our less-well known native trees, the Red Mulberry. And with a potential epidemic of Citrus Canker looming on the horizon, itís also a good time to remind people not to mail or move suspected canker specimens.
The Red Mulberry tree is a native Floridian that can bring rapid shade to our Florida Yards and attract wildlife with itís fruit. It is also drought resistant with few pests and is well adapted to most of our local soil conditions. But with rapid growth comes weaker branches and a shorter life which can be improved if the young tree is well cared for. It is most often noticed as a native tree in home sites that bring on the question posed by these new homeowners: should it be left in my Florida Yard? Information from Todayís column will address the pros and cons with information from Extension Horticulture Specialist Dr. Ed Gilman and from the Florida Department of Agricultureís Division of Forestry.
While there are three species of Mulberry trees that may be found in our area, the Red Mulberry (Morus rubra ) is the only native. The White mulberry (Morus alba) was brought to North America from its native China by the British in the 1700's. They tried unsuccessfully to establish a silk industry by using the Mulberry leaves as silkworm food. The leaves of this exotic are larger and lack the hairiness on the leaves of its American cousin. Another nonnative Mulberry commonly found as an escape in central Florida is the Paper Mulberry (Broussonetia papyrifera), which has very hairy leaves but lacks the blackberry-like fruit of the first two species.
Native Red Mulberry trees grow throughout all Florida except the southernmost part of the peninsula. They range throughout North America, often growing in the shade of larger trees. Normally they are found growing in rich, moist soils, but locally they volunteer in almost any habitat except for dry scrub lands. Another common location of Red Mulberry is along fence rows or utility lines because the seeds are deposited by the birds that eat the fruit.
Red Mulberries have wide spreading branches and a wide rounded shape. They can stretch upwards to a height of 35' - 40' and outwards to with a rough barked trunk of 12"-18" in diameter. (The Florida Champion Red Mulberry is in Jackson County and is 51 feet tall with a 65 inch trunk, while the National Champion in Oklahoma is 63 feet tall and has a 82 inch girth.) Some mulberries are known to live for 100 years or more, but few Florida specimens reach this ripe old age.
The leaves are alternate, simple, broadly oval in shape, sharp pointed, 3 to 5 inches long with toothed margins. They may have different shapes - some are unlobed, others look like 2-lobed mittens or while others are 3-lobed. Usually the different leaf shapes will be present on the same tree; occasionally, only a single leaf shape will occur on a tree. The undersurface of the leaves are hairy, especially along the leaf midrib.
Like its Ficus tree relatives, the Mulberries have milky sap. Some very sensitive people can get a rash from contact with the leaves or stems. Unlike the Fig trees, Mulberry trees will loose their leaves in the winter, and will have very attractive golden yellow foliage in the fall. This deciduous habit may make it unpopular with new residents that expect all Florida trees to have leaves all year round. The bark is smooth and light orange brown on young trees, but becomes furrowed and brown on older trees.
FRUIT FOR PEOPLE & WILDLIFE
Red Mulberry trees can have male and female flowers on the same plant (monoecious) or on separate plants (dioecious). Since flowers come from the current season's growth, a heavy pruning will reduce the amount of fruit that will grow that year. Flowering occurs in early spring and the fruits mature about two months later. The fruit resembles a blackberry, 1 to 1Ĺ inches long, are red when they are "green" (immature) and turn dark purple to black when ripe. They can be very sweet and edible. The large sweet fruits attract many kinds of songbirds; raccoons and squirrels compete with the birds for the fruits.
Although it is tolerant of air pollution, dry conditions, and resists most pests, the tree will perform its best on moist soils. Red Mulberry is not emphasized as a landscape plant because its fruits can cause staining of sidewalks, driveways or automobile finishes. There are some fruitless cultivars of White Mulberry available, but I have not heard of any non-fruiting Red Mulberry cultivars. True male selections could be used in the landscape where a rounded crown dense shade tree is desired. The best place for this tree in the landscape would be in the side or back yard where wildlife can make use of the fruit. Mulberry wood is rather light and soft, but very durable in contact with the soil si it has been used for fence-posts.
Mulberry trees are rarely available in the nursery - those specializing in Florida Native plants may have them in stock or can locate trees. Propagation of these trees can also be attempted. Seed from the fruit will require a cold stratification period before germination, and seedlings may take several years to achieve a reasonable size. A better propagation method is to root cuttings of mature wood from the current season's growth - this will result in an exact duplicate of the parent plant.
If you need additional information on Red Mulberry trees, visit your county Master Gardeners, or call or stop by your county Extension office. For those with other questions about Florida Yards, contact me - my phone number is 863-763-6469 and you can send e-mail to firstname.lastname@example.org.
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