Red, Hot and True

New and dramatic improvements in crape myrtle flower color add sparks of true red to our Independence Day gardens. And these vivid blooms don’t stop with the fireworks! Given the free-flowering nature of crape myrtles, these true red flowers will continue to grace our gardens throughout the sultry days of summer and on into autumn.

Breeding a better crape myrtle

Wild crape myrtle species from southeast Asia have flower colors ranging from white to pale lavender to watermelon-pink. Gardeners have long sought flowers with clearer and more intense colors but true red flowers have always been elusive. Finally, a few short years ago, Dr. Carl Whitcomb culminated long years of breeding with the introduction of Dynamite®. This was the first large crape myrtle with true red flowers — but not the last.

Dynamite® was widely acclaimed for its red flowers and became hugely popular, inspiring searches for more red-flowering crape myrtles. Dr. Whitcomb continued his breeding and went on to introduce Red Rocket®, Tightwad Red® and Siren Red®, each with a different quality. The U.S. National Arboretum also got into the act by releasing red-flowered ‘Arapaho’ and ‘Cheyenne.’ A few other selections have long been recognized for their good red flower color, but they never achieved the acclaim and notoriety as these later, improved selections. Thanks to the introduction and popularity of Dynamite®, red crape myrtles — new and old — are now very popular.

All sizes and shapes

Not only do we now have true red crape myrtles, but they’re available in different sizes to suit all your sunny garden needs. Single- or multi-stemmed tree-form crape myrtles are ideal as flowering specimen trees or as small, flowering shade trees near patios, walkways and entrances. Shrub forms make excellent accents in a shrub border when planted in groups. Dwarf plants are effective as large groundcovers, perennial bedding plants, or container plants, providing colorful summer flowers.

Tree-size crape myrtles grow more than 12 feet tall in 10 years. Semi-dwarf crape myrtles grow between 4 and 12 feet tall in 10 years, and dwarf crape myrtles generally stay below 4 feet, at least during the first five years.

Planting and Garden Care

All crape myrtles need full sun — the more sun the better. This is especially true with red crape myrtles, since shade or clouds can cause some selections to lose their red color. As with other crape myrtles, they are drought tolerant once established, but a little extra water will make them grow faster and bigger. The same goes for fertilizer: Crape myrtles don’t need much but will grow faster if fertilized.

When it comes to planting, crape myrtles are very tolerant and forgiving, with two exceptions. First, crape myrtles will not grow in wet soils. Second, never plant crape myrtle too deep — if you do, they will pay you back by not flowering for years and years.

For best results and low maintenance, choose a selection whose ultimate size fits its place in your garden. With the new selections now available, you can choose a red crape myrtle of any size.

Don’t commit “crape murder!”

Crape myrtles generally requires little pruning. If occasional pruning is needed to improve plant shape or form, do so anytime after leaves have fallen. However, avoid hard pruning that cuts stems or branches that are three or more inches in diameter (“crape murder”). This severe pruning results in excess leafy growth, sprouting and delayed flowering. It also spoils the beautiful winter branch structure on crape myrtle trees.

Tip-pruning to remove old flower clusters promotes reflowering but is not practical for large plants or low maintenance landscapes. Tip pruning is largely unnecessary on many newer red-flowering selections since they naturally repeat-bloom.

The future is rosy

Breeders are continuing to improve and introduce new crape myrtles. Watch for new dwarf crape myrtles from University of Georgia professor Michael Dirr, including a new red called ‘Cherry Dazzle.’ Dr. Whitcomb and the breeders at the U.S. National Arboretum are continuing their work. They hope to broaden the ornamental appeal of crape myrtles even further by searching for new flower colors as well as red leaf color that stays red all summer long. Stay tuned as the world of crape myrtles continues to expand!

About the author: Dr. Gary W. Knox is a Professor of Environmental Horticulture at the University of Florida and North Florida Research and Education Center. He serves as President of the Crape Myrtle Society of America.

For specific variety recommendations, along with ultimate mature heights, see the rest of Dr. Knox’s story in the July/August issue of Neil Sperry’s GARDENS Magazine. Click here to subscribe, or to order a back issue.

Don’t miss the 2005 Crape Myrtle Conference and the Annual Meeting of the Crape Myrtle Society of America, June 24-25. Click here for details!

Posted by Neil Sperry
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