Four large (14') hemlocks. The two that are mostly North facing (but still sheltered) are turning yellow from near the trunk outward. (the ends of the branches are still green). The Hemlock in the middle is getting really bad and it only started a month ago. The hemlock on the end (Northmost) is just starting to turn yellow in spots near the trunk. They get water by default when I water the garden. we fertilized this spring (for the first time in a decade) but were careful to keep the fertilizer around the out most branches. Under the trees are mulched. We put a white paper under a yellow area and shook it....only two tiny spiders showed up. Some little brown bits and some needles. When we shook the green area NOTHING fell out. We are totally stuck. Our neighbors landscaper layed a pile of broken pavers under the two affected trees ....I just saw them (and removed them) today. But the side with the pavers under it does not look worse than the front of the tree. I do not know what to do.