Illinois Extension Educator Richard Hentschel continues to discuss the now critical need to water valuable landscape ornamental and shade trees. Trees are the last of the plants to show wilting foliage as a symptom of a droughty condition. By the time that happens, watering is extremely important to survival. There are a variety of ways to water -- using a sprinkler, watering bags or an open-ended gardening hose in the drip line for established trees.