Do your trees/shrubs have Aphids or Spider Mites?
Aphids feed in clusters and prefer new shoots or young leaves. Most aphids are 1/10 inch long, and are commonly green, pink and black. Similar to a mosquito to humans, Aphids feed by sucking the moisture/water. This causes the plant to yellow, dry out, shrivel and even cause death of the plant.
Spider Mites are commonly found in mid to late summer. They thrive in the heat and put a lot of stress on the host plant. We commonly find them in Dwarf Alberta Spruces, Blue Spruces, Junipers, Fitzers and Tams. Spider Mites reproduce rapidly and can devastate a plant very quickly.