Garden Guru article on Crepe Myrtles by George Rogers:

How did midsummer roll around so fast?  The Crape Myrtles are showing off, so let's get a handle on them.   As with Magnolias, here's a plant group more comfortable to our north, but we do okay with them here.  In South Florida three basic types prevail, all of them originally Asian: 1) The good-old-fashioned original species Lagerstroemia indica, which has been with us for over a century.  2) A series of new and improved hybrids, such as the popular lavender-flowered, jumbo-sized "Muskogee" and the pink-flowered, economy-sized 'Tuscarora."  3.  Queen Crape Myrtle, L. speciosa, is eye candy.   Stay tuned a moment on this species.  The name Lagerstroemia honors Magnus von Lagerstroem, 18^th Century bigshot in the Swedish East India Company.   "Crape" reflects the resemblance of the petals to crinkly crape (crepe) fabric.

Crape Myrtle's big blossoms come forth mostly in the summer, sporting every hue in the reddish-purplish family. Honest-to-goodness red is unusual but available in "Dynamite." The hybrid "Natchez" has white flowers.

The plants are deciduous, but leaf loss is not altogether bad.  Colorful bark adds interest during the leafless months, there may be a little fall color, and the new growth can be eye-pleasing too.   Crape Myrtles range in size from ground covers to shade trees.  In our area, we're talking mostly large shrubs or small trees.  Most produce suckers and multiple trunks, so a treelike shape may require a nip and a tuck.  But just a little clipping: Crape Myrtles are not fans of extensive hard pruning.  Like me, they perform best without micromanagement. 

Discontented specimens are easy to find, so here are some tips on the pursuit of Crape Myrtle happiness.   The plants thrive in full sun and well drained, rich, moist soils. They prefer acid conditions but generally tolerate mild alkalinity.   Powdery Mildew is a fungal nuisance especially prevalent in hot wet climates like ours, minimized by avoiding wet leaves caused by overhead irrigation and poor air circulation.  The most popular selections locally are the mildew-resistant hybrids "Muskogee" and "Natchez."  The last-mentioned has the added benefit of resisting pesky aphids.

Queen Crape Myrtles are comparatively large sun-loving shrubs to potentially substantial trees, I think a wee bit more comfortable in South Florida than the other species.  The leaves can be a foot long and have distinctive lobes at the base.  The magnificent pink to purplish flowers are three inches in diameter in clusters a foot long. Although somewhat drought tolerant once established, this species prefers irrigation, fertilization to prevent pale nutrient-deficient foliage, and maybe a little shaping, especially around the base.  Queen Crape Myrtle makes a flowery focal point but remember they drop their leaves.

Sometimes I think the snowbirds have it all backwards.   Florida in the summer is great:  I-95 is a little less terrifying;   the living is easy; and the Crape Myrtles are pretty in pink.