Having not received significant rainfall in well over a month, plants in Southern Wisconsin are showing signs of stress. Compared to agricultural crops or turf grass, trees have well developed and substantial root systems that allow them to reach moisture that evades other plants. However, in a drought like this even established trees can become stressed.
Newly planted trees are the first to go. When a tree is transplanted it looses most of its roots, which gradually grow back over a 2-3 year period. For this reason, watering of newly planted trees is of great importance. Make sure there is a good layer of mulch around the tree (3-4″ deep) and give the area around the tree’s roots a slow a sustained flow of water. Applying the equivalent of 1″ of water per week over the root zone will assure that your tree will establish a healthy root system.
Mature trees are more difficult to water due to the size of their root zones, but may need attention as well. Certainly trees growing in difficult conditions (i.e. compacted soils, limited growth space, sun-exposed root zones, recent disturbance to the root zone, etc.) should be watered to maintain their health. Here again, 1″ of water within the tree’s dripline will be sufficient to bring the tree through this drought.
If you have any questions about how to care for your trees contact the Urban Tree Alliance for a free consultation.