So this picture represents your ideas and is not existing in real life? If so, I wouldn’t add any more trees. This seems heavily planted already with several things that don’t appear to be mature size yet.

I think a pretty tree in the front yard is always a good idea. I have a problem with your image, though. I strongly suspect the proportions are all wrong. With photoshop-type programs, it's easy to make an image in which the trees are much smaller than in real life. I'd look up the mature crown size and measure carefully. We have a lovely Japanese maple that some previous owner planted way, way too close to the house. There's nothing more depressing than cutting down a beautiful, thriving plant because it was planted in the wrong place.

The orange tree looks too close to the house, the conifers look too close to each other. Make a plan on graph paper and put in all the mature sizes of your planned plants. And not just the average size for a conifer, but the actual size of whatever cultivars you're planning to plant.

You might want to do this for everything, because I think your tulips are too big compared to the purple plant next to them. If that's a lavender or salvia, it will be bigger than it appears. In short, you can't use this image as a planting plan.

I suspect the river rock will be a weedy nightmare in the not-too-distant future and the curves will be hard to mow. I'd get rid of it.

I'd also consider a Silverbell or a Virginia fringe tree. Both should be native to you. The Redbud should be native, the Kwanzan cherry is not.

Silverbell at Landsford Canal State Park · More Info

I agree with Sigrid. A flowering tree in the empty center area would be lovely. I second the idea of a native tree. Check your N.C. native plant society website for ideas. I have redbuds, a fringe tree, native dogwoods including a pagoda dogwood which is native here in northern VA. Of course, although not flowering, a native oak would be the best tree to plant for its value to other species, its carbon sequestration, deep roots-it is considered a keystone species. We have ten on our half-acre along with plenty of other trees. One of my favorites is a sassafras tree which I planted last year.

Japanese cherry trees are short lived trees. I don't know if you care about that or not.

Here, redbuds get to a certain size, then the next bad ice storm takes them out. In that respect, they aren't dissimilar to Bradford pears, except because they are smaller, it isn't as big a mess when they explode.

When I was given a silverbell tree, I was told to plant it on a hill so I could look up at it.

Here it is. I don't think I planted it on a big enough hill.

Your silverbell (Halesia) is beautiful. Not native here, but might be for Jill in N.C.