In extremely hot/dry weather it is important to remember to increase your watering practices accordingly. Give each plant a thorough deep watering; too frequent shallow watering will hamper the root development. Watering should supplement any rainfall. Remember, it normally takes several hours of rain to amount to one inch of rainfall. Brief summer showers rarely add to the the moisture supply of trees and shrubs.
Roots of newly planted stock must not dry out completely for extended periods of time, especially during the first growing season. Such stress could kill the new plants. Water each plant thoroughly right after planting to settle the soil around the roots. The soil type, the amount of rainfall, and the temperatures govern the frequency and amount of water needed.
Dig and Check Method ::
Check the soil near the base of the plants to a depth of six inches (be sure to dig far enough away so that you do not damage the roots). Water when the soil feels dry. Do not water so often that the soil does not drain and remains soggy.
When watering your tree or shrub with a garden hose, allow the hose to run at a slow trickle for 1/2 to 1 hour on each plant. When using a bucket you can figure a 1.5" tree trunk will require about 20-30 gallons of water.
We highly recommended gator bags for watering newly planted trees. These bags hold 15-20 gallons of water, one is ideal for evergreens while the other is perfect for deciduous trees. Just fill up the bag every 5-10 days (depending on your soil type and the current weather conditions) and the bag slowly releases the water over a 10-15 hour period. The slow release encourages deep root growth.
Watering per soil type ::
Sandy Soils :: 2 waterings per week
Well-drained soils :: 1 watering per week
Clay soils/Poorly Drained Soils :: Less watering (use the dig and check method)
Potted Trees and Shrubs ::
Trees :: During the first 2 weeks they should be watered 4-5 times a week for 20 minutes. After that you can cut back to 2-3 times a week, then down to once a week depending on the weather. Make sure the trees do not go into winter with really dry soil. You may have to water into December (or until the ground freezes) if the ground has been dry during the late summer and early fall.
Shrubs :: Should get watered 4-5 times a week during the first 2-3 weeks, then decrease to 1-2 times a week.