Mulberry relative from eastern Asia

When it rains, it pours.

Among the plant-identification requests we got last week here in the herbarium, there were three separate questions about this very odd plant. I can't quite figure out if it is suddenly being noticed now or if it really is a recent introduction establishing itself quickly. I'm inclined to go with the first idea.

This plant is placed by botanists in what we call the "mulberry" family (or Moraceae), which, sure enough, contains the familiar mulberries. The mulberry family is a large group containing many thousands of additional species, most of which are woody (tree or shrubs) and found in the tropics. There are some important tropical tree members yielding timber, and, of course, everyone knows of figs (nearly 1,000 different species!). Those of you who are fans of "Mutiny on the Bounty" will remember the poor little breadfruit plants that got tossed overboard: breadfruit is another tropical species, with edible fruits, in the mulberry family.

But our Mystery Plant is not a mulberry, fig or breadfruit. This is a strange plant for our area, introduced from eastern Asia. It is potentially a tree although most often it is seen as a shrub. Large individuals can attain considerable size. It has hard, tough wood, and its roots are rather yellowish. Of particular interest will be the very stout thorns that are produced on some branches: They can be dangerous. The leaves are handsome, dark green and glossy. The plants are either male or female, that is, bearing either staminate or pistillate flowers, not both. (The term, of course, for such a species is "dioecious.") Whether male or female, the flowers are small and inconspicuous, held in little roundish balls in the spring. In the fall, the female flowers' ovaries swell into a fleshy mass, which takes on a sort of strawberry appearance, eventually turning red or orange. When the fruit gets ripe and mushy, it's ready to eat. (I've never tried it.)

The leaves, thorns and fruits that are produced by our mysterious plant might make you think of another mulberry-ish relative, the reasonably common "Osage-orange." It is normally a smaller plant with smaller leaves and produces a large, green, globose fruit that looks sort of like a brain. As long as you have the fruits of both species, so characteristic of each, you won't have any trouble telling the two apart. (Without the fruits, you might need a botanist's help.)

This species has been valued as a hedge plant, and because of its dense growth and the formidable thorns, it makes a fine "living fence." But before you go out and try to start planting some of it, be aware that it spreads easily, forming sprouts all over the place. Getting rid of this thing once it is out of control can be difficult. And then there are those thorns. It might be best to stick with something else for landscaping.

This week's Mystery Plant: "Strawberry tree," Cudrania tricuspidata.

John Nelson is the curator of the herbarium in the department of biological sciences at the University of South Carolina. The herbarium offers free plant identifications. Visit www.herbarium.org.