Asked August 31, 2021, 3:23 PM EDT
We have three spruce trees. We water them once a month (soaker house, run it for 1.5 hours), unless there is a good soaking rain. I notice that the needles on some of the lower branches sometimes turn brown. We consulted a tree service and they said that they needed a treatment of some sort, "feeding" the tree some way (we weren't totally clear on the details, but it was some sort of chemicals). We did the treatment, and the trees did get better, but then this year one of them again had brown needles. The soil may just be bad. Is this something that needs to be done annually, does this sound reasonable, or is there something else that I'm missing here, like maybe it needs more water? The treatment is a bit expensive, several hundred dollars. We like the trees so we'll do it if we need to, but I am wondering why the trees need this if they are supposedly native to the area.
Denver County Colorado