Help with Kousa Dogwood
I saw that another board member recently asked a question about Kousa Dogwoods, so I apologize if anyone feels like I'm asking about something that has already been answered. I wanted to see if anyone might could give me some advice about what's going on with my tree. A few weeks ago, I noticed the leaves starting to shrivel up some, with them becoming yellow/brown in the last week or two. Just this week, they have started to fall off. Each event (shrivel, color change, fall off) has begun at the top of the tree, and on the ends of the limbs.
If I remember correctly, this same thing happened last summer.
I'll try to give you as many facts as I can:
-I'm in Central Alabama (Birmingham), and the tree is in my backyard, in the standard Suburbia, USA neighborhood. It gets full sun. The tree was planted late Spring of 2013 (April-Mayish), and was about five feet tall at the time. It's now in the neighborhood of 6.5 feet or so.
-The soil in my yard is very heavy on the clay, and rock hard. When planted, I think I probably had a couple of inches of clearance all the way around the root ball, with the top of the roots sitting just above ground level once I put it in the ground. It was planted still in the burlap wrap, sitting on a pretty decent layer of Black Kow compost. As far as I could tell, I think I did everything pretty much exactly as the guy at the nursery told me to.
-It gets watered briefly every day by my irrigation system. In the past, I tried to do the occasional deep watering of my lawn, but because of the hard soil, water just pooled in the flat backyard, causing the grass to be uneven, while in the sloped front, it just ran into the road. To address that, I switched this summer to daily waterings of about 7-8 minutes per zone. Not ideal, but it has been less wasteful. I water around 8 pm each night, to try to let the water soak in as much as possible rather than be evaporated by the sun. I haven't noticed any fungus issues in my yard.
Overall the tree has done well, with very thick, green foliage earlier in the summer. It had no blooms last year, but did have a small handful (probably less than five) this year. I don't think this is an overwatering or drainage thing, because it was looking great two months ago, when Alabama was getting flooded every day. It didn't really leaf out until late April or maybe even May, though.
I feel like this is probably a sun/heat issue, but I don't know enough to know that for sure. I would note that for most of the last six weeks or so, those brief waterings each day were the only water it got. There has been virtually no rain since mid-June.
I'd greatly appreciate your thoughts.