Purdue Extension Service
Vanderburgh County, Indiana
Just when you thought you wouldn't hear me speak about this winter's ice storm any more....
I'm getting a lot of calls from people who had broken limbs in their trees. Some of these trees may have already been pruned, others are still contain broken limbs. The situation that is alarming these callers is that large amounts of water seem to be pouring out of the wounded areas. Is the tree bleeding to death?
What we are seeing is sap leaking out of the wound. This is sap that should have been going toward the limb that was removed. However, since the limb is no longer there, the sap has nowhere to go but out and then down the outside of the trunk.
In the spring, all trees start sending water, minerals, and carbohydrates upwards into the tree, to allow the opening, expansion, and growth of buds, leaves and shoots. This will occur throughout the growing season, although it does tend to slow down during the summer and fall.
Some tree species, such as maple, birch, dogwood, elm, walnut, and yellowwood, have an exceptionally heavy sap flow in the early spring. When pruned or wounded, these trees will noticeably "bleed" sap. Under normal circumstances, we generally try to hold off pruning these trees until mid summer or late fall, when the sap flow is slower. However, the ice storm and subsequent repair work forced us to do some tree work at a less than ideal time.
Again...this isn't hurting anything, so there's no reason to worry. The other parts of the tree are not being deprived of sap, so the overall health of the tree is not going to be affected. The "bleeding" may be objectionable from a cosmetic standpoint, especially if the sap is dripping directly onto people, cars, and other things directly beneath the tree.
We do not recommend trying to put a "bandage" on the tree by spraying or painting it with a wound dressing. As the tree wound begins to seal off, the sap flow will stop on its own. Also, with many trees, the sap leakage is so strong that it tends to wash the wound dressing off anyway!
The best advice is to water the yard during dry spells, starting now. This will help the tree speed up the recovery and sealing over of the wounds.
I will be talking about storm damage and trees this Saturday at the Tri-State Home Show. You can find my speaking times in the advertisements elsewhere in today's paper. My Master Gardeners and I will also be hosting a booth inside on the main floor of Roberts Stadium. We'll have information on a wide variety of subjects, including the Master Gardener Plant Sale in May, and the Garden Walk in June.
For more information, contact the Purdue Extension Service at (812) 435-5287.