Pruning trees properly to avoid oak wilt

Keep Wimberley Beautiful Volunteers

Oak wilt is caused by a fungus passed from tree to tree through the root system — a destructive disease affecting live oaks and red oaks in central Texas.

Beetles and other insects can carry oak wilt from tree to tree that have a new, open wound caused by wind, hail, wildlife or pruning. Think of all the trees that were damaged last winter during the ice storm. It is critical that a damaged oak immediately be painted at the fresh open wound. Any kind of paint or wound dressing is acceptable, but the key is to do this immediately after the damage or pruning occurs.

Oak trees in central Texas can be divided into two groups: red oaks and white oaks. Red oaks are the most susceptible to oak wilt. The common red oaks in Texas are Spanish oak, Shumard oak and Blackjack oak. Live oaks, which are very common in central Texas and considered in the white group, are more resistant to oak wilt and are better at fighting off the disease. Still, they too can die from this infectious disease, especially when one tree becomes infected in a group of live oaks. The disease will spread through the root systems.

The spread of oak wilt is most prevalent in the spring. To prevent this, avoid pruning from February to the end of June. The best time to prune is in the late fall. During the coldest days of winter or during the heat of the summer is also an acceptable time to prune oaks. So, if you are thinking of pruning your oak trees, now is a good time as it appears as though the extremely hot, dry weather is here to stay for a while.

It is very important to immediately remove the damaged limbs and burn, chip or bury them. Clean all pruning tools with something like bleach or Lysol in between pruning trees to avoid the spread of the disease.