There are different types of Magnolia and Dogwood trees that would be the size you want (like a star magnolia or Cornus florida (Flowering Dogwood). They should be a good fit though I don't know about the roots, you would have check into that more.

Thanks for that. I'm not sure about a dogwood since they seem to not last very long in my area. I'll look into a star magnolia.

Star magnolia is indeed a beautiful tree, but it's very dense and compact, and most cultivars are more like large bushes than trees. Maximum height is about 15 feet. If sweetbay magnolia (M. virginiana) grows in your area, look into that--it's open, graceful, and airy and often multitrunked, and offers a dappled shade that's very appealing. It's a lovely patio tree to about 25-30 feet.

What you call dominating, another may call providing nice shade.

Given the fact that you seem to be scared of size (for a tree, 15-20 feet is nothing), you may be better off looking at some of the columnar trees out there, from maple to oak to pines...there are many more, I'd look at what local nurseries have to offer.

My best recommendation is to find a bunch of magazines and books and bedge out one weekend and when you find the pictures of what you want, see how that can be adapted to your situation.

What I have noticed is people sit down and think about size and think 20 feet is a huge number...but when they drive down a neighborhood with large shade trees, they appreciate the size, stature and grandeur of monoliths many times the size of what scared them on a blank piece of paper.

As for the roots...yeah, you're going to find the answer you want to hear. Potentially, any plant could create a problem...they all have roots, the vast majority of which are shallow, but plants are marvelously adaptable organisms, thankfully, and can find a way to live and thrive even given the usually artificial expectations we have for them. Most of those shallow roots are very small, and even the larger ones...I've yet to hear of a small tree (in age and corresponding size) causing any upheaval. This is a condition of age and size.

If roots truly are an issue for you, vines and arbors. While providing a different appeal than a tree, this can create a stunning effect that a tree can't.

Also, some of the larger growing shrubs, PG Hydrangea, viburnums of all flavors, about seventy others. Trim them to a single trunk and voila! a tree you have.

One of favorite trees in this size are standard fruiting pears. However most people wouldn't want them due to some of the fruit rotting.
Mexican Plum or some type of crab-apple would be what I would pick. The Crepe Myrtle is also a consideration. These would all be in the size mentioned, flowering, hardy, and not too messy.

perhaps a chionanthus(fringetree), either c. virginicus(native) or c. retusus.
both are pretty in bloom during spring.
even a crape mrytle might be a good tree/large shrub for your site, though they are commonly planted throughout the southern u.s.
this is a mature specimen of american fringetree over 20 years old and within the size limits you desire. the flowers are fragrant, too.
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