The health of your spruce trees and other evergreens depends greatly on their watering schedule. Spruce trees include Colorado blue spruce, Columnar Blue spruce, White spruce, Fat Albert spruce. Junipers include Wichita, Cologreen, Moon glow, Sky rocket and other upright junipers. We have seen many evergreens in Calgary die due to over watering and under watering. Evergreens are more sensitive to watering conditions than other trees so you need to make sure you are watering them appropriately. It can be tempting to continue watering your evergreen when it looks like it is unhealthy but quite often too much water is the source of the ill health. So by continuing to water, you can harm the tree further. We have found that watering newly planted evergreen trees once a week during summer is adequate. This watering schedule can vary of course with temperature changes.
Spruce trees do not need to be kept constantly moist. In fact, the trees should be allowed to dry out between watering. Water sitting for too long around the root ball can cause the roots to rot. You can purchase a water meter from your local garden center to test the soil for moisture. This simple device will give you an accurate reading of the moisture content below the surface. It is important to remember that although the surface of the soil around your tree may be dry the subsurface can be moist.
Watering your tree in late fall just before freeze-up is vitally important to the health of your tree. Evergreen trees use water from fall and early spring to nourish them throughout spring and summer. Your sprinkler system may have been blown out before the final watering is needed so you will need to hand water your evergreens instead of relying on your sprinkler system.
Watch for signs of over or under watering like yellowing of needles, dropping needles and brownout on one or both sides of the plant.