Friday, August 26, 2016

Crape Myrtles

If you drive around Memphis, you'll be hard-pressed to find a home without a crape myrtle in the yard. Although in the past few years (since we've been battling crape myrtle bark scale), I've seen people remove them (or at least attempt it: they tend to re-sprout from the root). Still, I think most of us still love them, in spite of this new problem they're having. The young plants can be a bit gangly for the first few years, but if you are patient, they can become something truly beautiful. The branching structure of some varieties is a work of art. 

Consider, this huge, old 'Natchez' cultivar that belongs to my neighbor. He estimates that it is about 30 years old. While its lovely white blooms are almost finished, its bark and beautiful branching structure makes it a great tree year-round.

Here is a closer look at that massive, branching trunk. 

Natchez is one of the larger crape myrtle varieties, growing to over 30 feet tall. Jack and I bought one 4 or 5 years ago. One of the things we liked about it was its exfoliating bark, which peels away each year to reveal smooth, cinnamon colored wood. It takes several years for a young tree to develop this trait. 

In this picture of our young tree (at right), you can see three older trunks that have exfoliated and two younger ones that still have their immature color. Some of the peeling bark is visible at the bottom of the picture.

It's amazing how many different varieties of crape myrtles are available. In addition to an assortment of bloom colors, you can have your choice of size (3 ft. to over 30 ft), leaf shape (rounded short leaves to longer thin leaves), and bark texture. 

How did all these choices become available? I learned a lot about this subject from the speaker at this month's Master Gardeners meeting. Greg Touliatos of the Urban Earth garden center, spoke about crape myrtle bark scale, and in his introduction, gave us some history of the crape myrtle. 

The first species of crape myrtle, Lagerstroemia indica, was brought to the United States over 200 years ago. While a beautiful plant with long-lasting flowers, this variety has a smaller, bushy form and is prone to mildew and winter die-back. Around 1950, U.S. Arboretum personnel acquired seeds from Japan of a different species of crape myrtle (Lagerstroemia faurier), which has a taller, more upright form, is more cold hardy and less susceptible to mildew. They began to experiment with growing this species, and soon began to develop hybrids with the most desirable characteristics of both species. These hybrids are usually what we find at most nurseries today.

For years, we've enjoyed the beauty of these hybrid crape myrtles and considered them to be "bulletproof," pest-free and requiring little care. However, in the early 2000's, a new form of bark scale that infests crape myrtle found its way into the U.S. and began making its way across the country. Scientists still have much to learn about this new scale, but there is suspicion that some varieties of crape myrtle, specifically those bred from the Japanese species Lagerstroemia faurier, may be more susceptible than others.

The neighbor's huge crape myrtle (shown in the pictures above) was infested two years ago with crape myrtle scale, and he had it treated at that time. It has completely recovered and he has not seen any new infestation. So I suppose there is hope that we will not have to treat our crape myrtles every year. Only time will tell what the ultimate impact will be of this new type of scale. Until we learn more, crape myrtle lovers will need to be vigilant about inspecting their trees for infestation.

The presentation on crape myrtles will be given again in September at the Urban Earth Saturday seminars. Check their website or Facebook page for more information.

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