Evergreen Trees, Kent Island, Queen Anne County MD
I planted about 150 mixed evergreens last October in 2016, a combination of Eastern White Pine, Canadian Hemlock, Norway Spruce, Serbian Spruce, and Nellie Stevens Hollies. They were 6-7' trees from a reputable tree farm in Pennsylvania. About 25 of them died, beginning in May, after we had several days of rain, and continuing to fail through the summer - this summer 2017. They were watered regularly (once every 8-10 days) when we did not have rain throughout the summer. The trees tended to lose color, and sort of turn grayish or dingy (not the yellowish color that occurs in fall needle drop) , and then turn brown and die. This October, about 3 weeks ago, I replaced the dead trees with another species (Green giants Thujia) , and some new Norway Spruce. Some of the remaining healthy trees, like the hemlocks and Spruce appear to have a lighter green color than the new dark green color of the new trees. They don't appear to be in danger, but they look like they are possibly not getting enough nutrients . The tree farm recommended that I get a soil test done - and did so at Un of Delaware, who includes your department in their report. The Ph is 5.5, the Phosphorous is quite low at 12, the potassium is 39, the magnesium is quite high at 140. The soil sample was taken in a couple places near the failing trees, but at least 6-7 feet away from the drip lines. My question is, should I purchase some triple phosphate and try to improve the phosphorous count? Could that be the reason the trees appear to not be getting nutrients to the feeder roots? My perennial garden with peonies, russian sage, and Oak Leaf hollies seem to have yellowish leaf color also. Thank You, Stevensville, MD
We viewed your photos. Losing 25 trees out of 150 is not bad. When plants decline within the first year of planting it can usually be attributed to environmental and site conditions such as poor planting techniques, lack of establishment, poor drainage, poor soils, etc. You will have to check for this. The trees are large specimens. A smaller tree is more economical and will establish much quicker than a large tree. Less root system is disturbed and is easier to keep the root ball watered. See our website for planting techniques
The pH is ok. You can add phosphorus around the root zone of the plants as a top dressing. This will help with root establishment but not so much for the yellow color. We notice that the trees are planted in the lawn area. f the lawn is being fertilized the trees will benefit from the nitrogen in the lawn fertilizer. Keep the trees well watered up until the ground freezes this winter and through the next growing season. Keep mulch no thicker than several inches and away from the base of the trunks.