Ask Mr. Smarty Plants

Mr. Smarty Plants is not aware of many native trees that are only 10 feet tall, but there are several shrubs that could fill the bill. But first, lets address the tap root issue. This publication from Iowa State University Extension describes the different types of root systems, and I've excerpted the passage below from a previous answer which describes different root types.

"Although trees are generally divided into two groups by root type—tap root trees (such as oaks, hickory, walnut, conifers) and lateral, or fibrous, root trees (maples, ash, cottonwood)—this distinction is most evident as seedlings or saplings. Once the tree is planted and begins to mature, the distinctions between the root types become less pronounced. Then, the depth and lateralness of the roots is greatly dependent on the soil condition. Highly compacted soils, soils with low oxygen content and soils where the water table is near the surface are not likely to produce a strong tap root. Their roots are more likely to be lateral and located very near the surface with the majority of the roots located in the top 12 inches of soil. Also, it is important to realize that the spread of the roots can be at least 2 to 4 times greater than the drip line of the branches.

You can read the recommendations from Iowa State University Extension Service for Sidewalks and Trees which bases the distance trees should be planted near pavement on the mature height of the tree. Their recommendations are:

1. trees with a mature height of less than 30 feet, 3-4 feet from pavement,
2. trees with a mature height of 30 to 50 feet, 5-6 feet from pavement,
3. trees with a mature height of greater than 50 feet, at least 8 feet from pavement."

And now to the plants. Since I am not aware of the growing conditions in the flower bed you are planning, I'm going to tell you how to do a Combination Search in order to come up with a list of plants you may want to use.

Go to the Native Plant Database page and scroll down to the Comnination Search box. Make the following selections; select North Carolina under State, Shrub under Habit, Perennial under Duration. Check Part Shade for Light Requirement, and Moist for Soil Moisture. Click on the Submit combination Search button, and you will get a list of plants that fit those criteria that should grow in your area. Clicking on the name of each plant will pull  up its NPIN page that has decriptions, growth requirements, and photos.

Here are three plants that I came up with from such a search:

Amelanchier canadensis (Canadian serviceberry)   (more images)

Kalmia latifolia (mountain laurel)  Be aware that the plant is considered toxic. (more images)

Morella cerifera (wax myrtle)

For some help closer to home, you might contact the folks at the Forsyth County Office of the NC State University Cooperative Extension.

Morella cerifera