Standard Mulberry Growth and Hardiness

• A standard fruitless mulberry (Morus alba) grows 2 feet per year in ideal conditions. This is considered a fast growing shade tree that can grow upwards of 50 to 60 feet. Mulberries can withstand temperatures down to minus 30 degrees Fahrenheit (or USDA plant hardiness zone 4) and are considered very hardy. In locations that mulberry trees are borderline hardy enough for, tip die-back can occur and stunt the growth of a tree.
  
  

Planting Depth

• If you live in zones 4 through 8, planting depth may be the cause of stunted growth. A tree will suffer from being planted too deep or too shallow. A fruitless mulberry tree that has been planted too deep will suffer from girdling -- a rotting or removal of the bark and cambial layers of tissue. Cambial layers carry precious water and nutrients to the tree canopy, and a tree suffering from this -- either by planting too deep, rodent damage or string trimmer damage -- will have a stunted growth rate or die. Shallow plantings will cause dessication, or drying, of the roots.
  
  

Diseases and Insects

• If your fruitless mulberry has been properly planted, the next thing to check for is disease and insect infestations. A few diseases that plague fruitless mulberries include root rot, blight, canker and slime flux, also known as wet wood. Insects that can become a problem include mites, scale, mealybugs, webworms and root nematodes. Trees that are stressed due to disease and insect damage can exhibit a slower growth rate, lose foliage or die, in severe cases.
  
  

Other

• Other factors that play into the stunting of a tree can be environmental, mechanical or cultural. Fruitless mulberry trees prefer to grow in full sun, in a moist, well-drained fertile soil. Although considered drought tolerant once established, a fruitless mulberry will grow faster with proper watering and fertilizer. Check for mechanical injuries due to lawn mowers, browsing deer, wind damage or large cracks. Check with you local extension agent to learn more about pest problems that might be affecting your particular location.