• Middle-aged weeping willowAmerican Images Inc/Photodisc/Getty Images
  
  Willows are a notoriously short-lived tree, for all their ornamental beauty and graceful growing habit. A native of Asia, the willow can and does thrive all over North America. Unfortunately, it will rarely survive more than 30 years, and problems may begin to become apparent after 20 or so. Watch for signs of trouble, and with careful pruning and maintenance for this litterbug of a tree, your willow can stay healthy and beautiful. Its extensive root system will continue to stabilize large areas of soil long after the tree is gone.
  
  

Height and Foliage

• Mature weeping willows are tall, topping out at 45 to 50 feet, bearing a great deal of weight in their large branches. If they've been given enough space and sun to grow properly, they will have multiple trunks with a broad, rounded crown. Long branches will trail to the ground with long, narrow leaves covering their length. Willows have beautiful, yellow foliage in the fall, and branches are a bright yellow just before they bud in spring.
  
  

Bark, Trunk and Branches

• As willows age, they become vulnerable to cracking, breaking and splitting, both in their branches and at the crotches where large, heavy branches meet the trunk. Willow wood is naturally brittle, and height makes it vulnerable to storm and ice damage. Prevent this condition by pruning for strong structure when the tree is young, but you will notice more falling and splitting branches as the tree nears the end of its lifespan.
  
  

Pests and Diseases

• The older the willow, the more vulnerable it is to infestations that can further weaken an aging tree, especially through cracks and wounds in branches and trunks. Aphids and boring insects can penetrate the bark and kill leaves, decreasing the willow's vigor and sometimes girdling and killing the tree. Mature willows are also a favorite haven for gypsy moths, which nest on and eat leaves in their larval stage. Old willows are also more prone to fungal diseases like root rot, which can enter through shallow surface roots damaged by mower blades over time.