Ask Mr. Smarty Plants

With very few exceptions, there are no shrubs that will grow in Florida that will not get taller than 3 ft. very quickly. Your sub-tropical climate and normally frequent rains are an inspiration to most shrubs to head for 6 to 8 feet. So, you may find dwarf varieties of some plants native to your area. These cultivars (cultivated variety) or selections are being developed by growers all the time. Since the Lady Bird Johnson Wildflower Center is dedicated to the use, protection and propagation of plants native not only to North America but to the area in which they are being grown, we will first look in our Recommended Species List, selecting Florida on the map and then "shrub" for General Appearance. Since you did not say if you needed plants that tolerate shade or full sun, we will have to leave that specification off. One excellent foundation plant is Ilex vomitoria (yaupon); you will definitely need a dwarf version of that. Follow the plant links to each page on that plant to find out its normal size, whether or not it is evergreen, and what moisture and sunlight requirements it has. 

Short Shrubs  for St. Augustine, FL:

Callicarpa americana (American beautyberry)

Gaylussacia dumosa (dwarf huckleberry)

Ilex vomitoria (yaupon) - you will definitely need a dwarf of this. Here is a list of references.:

     'Schilling's Dwarf'

     'Nana'

     'Stokes Dwarf'

     'Micron'

Malvaviscus arboreus (wax mallow)

Vaccinium myrsinites (shiny blueberry) - more information from Floridata

Chasmanthium latifolium (Inland sea oats) - This is actually a grass, 2-4 ft. tall, with graceful seed heads that bend over. It makes a nice short hedge and is a shade plant.

From our Native Plant Image Gallery:

Callicarpa americana

Gaylussacia dumosa

Ilex vomitoria

Malvaviscus arboreus

Vaccinium myrsinites

Chasmanthium latifolium