Hot dry summers and winter winds can often cause damage to trees and shrubs. Drought reduces the amount of water available in the soil that trees can take up. Injury to the tree occurs when more water is lost through transpiration than is available in the plant.

Symptoms of drought stress include: wilting of foliage, sparse canopy of off-color and undersized leaves, leaf scorch, yellowing, and premature fall coloration. Closer inspection of the branches will reveal twig growth and small, poorly formed buds. Prolonged drought will cause branch and root death and dieback or death of the entire tree. De-icing salts and fertilizers can compound the situation burning root and leaf tissue. Drought stress often weaken trees, making them more susceptible to attack by some fungi (root rots and branch cankers), and wood boring insects that come in to “finish off” a dying tree.

Some species of trees and shrubs are more susceptible to droughts, while others can withstand dry conditions. Trees such as maple, dogwood, ash, beech, linden, and tuliptree tend to be effected by droughts more than oaks, elms, and honeylocust. Newly transplanted trees are very suceptible t damage from dry soil conditions because they have lost approximately 90% of their root systems when they are dug and moved.

Preventing Drought Damage on Trees and Shrubs

• Mulch Your Trees – applying a thin layer (3 inches) of mulch on the root systems out to the tips of the branches (dripline) mimics how trees grow in the forest and will help retain moisture in the soil.

• Water – always water newly planted trees (rain or shine) on a weekly basis with approximately 10-20 gallons per inch diameter of tree. Put that water on the rootball, where it is needed and don’t just water the lawn with a sprinkler. Consider using water devices such as Treegators or Oozetubes to allow for slow deep soil watering on the root systems of newly planted trees. For older trees, mulching will help, but sometimes it is necessary to provide water to older trees to assure their survival. Using rainbarrels and drip hoses will help you save money and recycle stormwater that impacts are streams. For healthy growth, trees require approximately 1 inch of rainfall each week.

• Pruning and Fertilizing – During droughts, avoid pruning healthy live branches and fertilzing trees and shrubs. Prune dead wood only and use slow release fertilizers to avoid drying out roots and promoting leaf growth that a stressed root system can not support

• Pest Management – Scout for insect and disease problems on drought stressed trees and shrubs. Look for cracks in trunks and branches, small holes in trunks where wood boring insects emerged, sawdust or sapflow, and branch dieback. It is best to keep the tree healthy by mulching and watering than trying to control insects and diseases that are attacking a stressed plant.