Ask Mr. Smarty Plants

Savannah Holly is a trade name for Ilex x attenuata which is an older selection of a cross between North American native hollies Ilex cassine (dahoon) and Ilex opaca (American holly). Notice the "x" in the center of the Latin name, that means it is a cross or hybrid. We have no hybrids in our Native Plant Database, but will try to find some general information on pruning this particular holly.

This Floridata website says it can be grown as a large pyrimidal shrub or a small tree. You can also get some ideas of how this holly can be shaped by looking at these images from Google.  From a gardening Know How website, we found an article How to Prune Holly Bushes. From About.Com: Landscaping we excerpted the following paragraph from their article Winter Landscaping and Holly Plant:

"To give your holly a shape of your own choosing, prune back the tips of the current season's growth in late summer, autumn, or winter. If you have an old holly plant on your landscape which you wish to rejuvenate, Bunting has some tips on pruning holly shrubs. Bunting advises that you "'hat rack' it in late winter by cutting back the branches by half to three-quarters of their length. The remaining plant will have few leaves and look like a hat rack, but in spring it will flush out with new foliage from all the pruning cuts. In two to three years, it will be fully covered in leaves. Hat racking will result in a plant much reduced in size, but still full of foliage."

As far as we are concerned, that comes as close to the practical advice you are wanting. You are not going to get overnight results, but if your holly is overgrown and shapeless, you will eventually attain the look you have in mind.