In July 2014, 2 6' hollies were planted in front of our house, surrounded by 5" of river rock, not mulch. (Rock was here when we moved in.) Earlier this year, they both had yellow leaves and several dead branches all over the trees. Landscaper put a fertilizer spike in the soil; they did better for a while. One did more poorly than other, and it is now covered with leaves that are turning yellow and falling off. Entire tree is affected. I tried to take soil sample. All very dense clay below the rock. About 6" down, hit standing water. Other tree, planted 12' away is fine. Not as much clay; no standing water. Suggestions?
Also, ivy was planted last year in area between rock and front sidewalk. Trying to create ground cover. Not spreading as fast in part that gets more sun. Leaves also yellowing. Planted in garden soil (bags from Lowes) over clay, about 3". Soil is moist though top half-inch layer is dry. Not sure if can root in the dry soil (which has a lot of mulch in it--as part of the soil in the bag, not landscaping mulch). Suggestions to encourage growth? Other ivy in yard has much bigger leaves than the ivy planted last year by the landscaper. (He has not been helpful. Just blames deer and wet weather over the phone.)