Carolina Cherry...Sickly...Please help

Carolina Cherry experts please help...

I bought what was supposed to be a Carolina Cherry from my local large chain nursery. It was a 24" box. The tree didn't ever look particularly healthy, even when it was at the store. But, their selection was incredibly limited and I had to have a tree per HOA regulations. People describe the Carolina Cherry as having dark green leaves but the leaves on mine are medium green at best. Actually, my tree looks nothing like a Carolina Cherry from the pictures that I have seen of others' online. The leaves are the same shape but that's pretty much all they have in common.

Problems:

First, the tree is mostly bald. I'm not sure if you can see in the picture but it doesn't have a lot of leaves on it and many of the branches are quite bare. There is, however, new growth on the ends of the branches, just the interior is balding.

Second, a lot of the leaves are now turning yellow. I looked online and many said that it is a sign of overwatering, but yellow leaves from overwatering look in the online pictures to be at the ends of the branches, not randomly all over the tree like mine has. ALSO, there has been a lot of NEW, healthy growth on the ends of the branches in the one month since I planted it. It's like the tree is healthy and unhealthy at the same time.

I live in Las Vegas and these trees typically do very well here after they are established. I live in an area where the ground is extremely hard and clay-like with poor drainage. The landscapers put it on an adjustable bubbler and I have turned them off around the tree in fear that it is being overwatered.

I really need help with this. My 20+ other plants and 1 California Pepper tree are thriving. This is the only one that is giving me a major headache.

Yellow leaves can be a sign of many things. With 100+ degree days my thoughts would not be overwatering being the problem. Did the tree have yellow leaves when you purchased it? Also, do you know how often the tree gets watered, for how long, and the gallons per hour rate put out by the emitters (bubbler)? Oh yeah and how many emitters are on that tree?

I have a couple questions.

Does this Carolina Cherry = Prunus caroliniana? If so, is Carolina Cherry normally an broadleaf evergreen species - meaning, it holds green leaves through winter/dormant months?

According to PlantFiles, it is: http://davesgarden.com/guides/pf/go/57865/

If so, then you may just be experiencing this plant shedding old foliage - previous years leaves turn yellow and drop off. This is especially likely if all the yellowing and dropping leaves are interior and on old wood. The new growth of this year should be on terminal of branches and branchlets, and that sounds like what you've described as the healthy new growth.

Finally: none of the above is to say that you couldn't have some sort of watering problem, but you sure don't want yellowing foliage and declining tree health to be the time you figure it out. Invest in an inexpensive soil coring probe, and pay attention to what is going on below ground while you get used to caring for this new tree. A simple soil coring probe can be jabbed into the ground, and withdrawn to contain a core of soil 6-12" deep. This way you can determine instantly whether the soil below grade is dry as toast, evenly moist, or overly saturated.

This is much less expensive than continually buying, planting, killing, and replacing the same tree over and over.