A Guide to Growing the Fruitless Mulberry Tree
The fruitless mulberry tree originated in China. It was initially brought to North America by people who wanted to make money from silk, as the fruitless mulberry is the sole source of food for silkworms. Although the silk industry never took off in North America, the fruitless mulberry tree did and it started to be a popular landscape tree.
What people liked best about this type of mulberry tree was the fact that it was fruitless. People were not overly fond of mulberry trees because they grew fruits which were very messy. Not only did they stain clothing but birds made the ground a mess eating them and then carried the seeds away, scattering them about to make new trees. In fact, in some cities and states, the mulberry tree is considered an invasive species and it is banned.
The fruitless mulberry tree has a round top and can grow to be between thirty and sixty feet high. Its leaves take several shapes and can range in color from a light green tinted with yellow or orange to leaves which are dark green.
The silkworm weaves the thread from which silk is made. Most of the silk in the world is made in the countries of the Far East, especially in China and Japan. The silk farmers feed the fruitless mulberry leaves to the silkworm caterpillars, who then spin it into threads to make their cocoons.
The fruitless mulberry tree grows quickly and is an ideal city shade tree. It is able to handle pollution and also ocean salt water. The tree is easy to grow and not fussy about the soil. It likes to be planted where it can receive full sun. It will thrive in parks or yards with lots of space for it spread out. It can grow to be up to twenty-five feet wide.
This mulberry tree grows best in USDA hardiness zones 5-6. It becomes dormant during the winter. The fruitless mulberry needs to be pruned back dramatically at least every two years. The tree will regain growth of at least 15 to 20 feet the next summer. If the tree goes more than two years without pruning, you will need to hire a professional tree trimmer as it will be considerably overgrown.
This type of pruning is called pollarding. If the pruning is not completed, the tree can develop problems with weak crotches. They can allow moisture in and cause the branches to rot and fall off. This is one of the few problems with the trees as they are quite resistant to insect pests and diseases.
Not only is the fruitless mulberry tree considered invasive in some areas, a different problem with the tree is reported in Arizona and other parts of the Southwest, where many people go to escape from their allergy problems. The tree has been the subject of great controversy in some cities and has been banned in many. The reason is that the trees give off too much pollen which triggers allergies.
Ever since the 1950s, the fruitless mulberry has been planted in great quantities because it is a shade tree that is very easy to grow in a region which has endless sun and heat. The problem is that only the male varieties were planted because it was the female trees which grew messy fruits. The male trees give off huge amounts of pollen. Currently there are bans in Las Vegas, Phoenix, Tucson, El Paso, Las Cruces, and Albuquerque.
If you live in a warm planting zone and there are no restrictions on growing the fruitless mulberry, you may be very happy with this species. It grows very fast and is practically impossible to kill, no matter how much you neglect its care.