I have a newly planted tree (7 mo's old) and I have been deeply watering it occasionally. I have also used those fertilizer steaks as well. I have noticed a few of my leaves are turning brown and some included a few groups are totally brown. What causes this? Did I over fertilize? Is this possible even if you give it lots of water? Not sure how often I'm suppose to water, but when I do, I'm out there for at least good 5 minutes soaking it, let the water seep in, soak it again and do this countless times. The rest of the tree is bright green.