Pick the best crape myrtle variety for Pa. winters
Q uestion: I want to know if the crape myrtle I purchased in North Carolina will survive our winters. I purchased the medium size plant (12 to 15 feet) and the one that is the hardiest variety. I would love some tips on what to do to keep it alive for years to come.
Answer: Crape myrtles (Lagerstroemia species) are a quintessential southern plant that can be grown as a tree or a shrub. With attractive bark and form, crape myrtles are pretty even when there are no blooms in sight.
But, when they’re in flower, crape myrtles put on quite the show. In late summer, they produce clusters of brilliantly colored blooms that can be various shades of pink, red, white and purple. Their fall foliage color is often very pretty, too, depending on the variety.
There are several different species of crape myrtle with dozens of different named cultivars. Typically, crape myrtles are not reliably winter hardy this far north, but with some recent breeding breakthroughs and warmer-than-usual winters, some of the hardier crape myrtle selections can and do survive our Pennsylvania winters. Among the hardiest of crape myrtle varieties are cultivars of Lagerstroemia indica x fauriei such as “Hopi,” “Arapaho,” “Tuscarora,” “Tonto” and “Natchez.”
No matter their species or variety, all crape myrtles bloom on new wood, which means their flower buds are generated on the growth that occurs during the spring and early summer of that year. Because of this, crape myrtles can die all the way back to the ground during particularly cold winters and still produce blooms the following summer. Unlike plants such as magnolia that form their flower buds the season before, crape myrtles will not lose their flower buds to late spring frosts.
Gardeners in growing zones like ours, whose regular winter temperatures fall below the 20s, need to select the most winter hardy of all crape myrtle varieties. But, even with these hardier types, the plants still may not make it through the winter.
Often the plants will die all the way back to the ground and only sprout new growth from the soil, rather than from the existing branches come spring. In years following total winter die back, the growing season may not be long enough for those new shoots to produce blooms, so you should be prepared to take some extra steps to help the plant through the coming cold temperatures.
There are three things you can do to improve the chances of your crape myrtle surviving the winter.
1. Grow your crape myrtle in a large container. Much like overwintering a tender fig or other non-hardy tree or shrub, simply drag the entire pot into the garage or a cold cellar for the winter and let the plant shift into dormancy. Water your crape myrtle sparingly every six weeks and move it back outdoors when warm spring temperatures arrive again.
2. Mulch your crape myrtle heavily. After fall’s first few hard frosts, surround your crape myrtle with a cylindrical wire cage that covers at least the bottom half of the plant. Then fill the wire cage with autumn leaves or loosely packed straw, stuffing it in between the branches. This layer of insulation improves hardiness and encourages new growth to come from the branches rather than from the ground.
3. Trench your crape myrtle. A third and final option is to partially dig up your crape myrtle so the plant can be laid on its side. Then, dig a trench that’s as long as the plant is tall, and lay the partially dug crape myrtle down into the trench. Toss the backfill soil over the horizontal branches or cover them with a mixture of straw, leaves and the soil. To make it easier, you can tie the branches together with twine prior to laying it down into the trench.
With one of these three methods in place, your chances of success will be greatly improved.
Horticulturist Jessica Walliser co-hosts “The Organic Gardeners” at 7 a.m. Sundays on KDKA Radio with Doug Oster. She is the author of several gardening books, including “Attracting Beneficial Bugs to Your Garden,” “Good Bug, Bad Bug,” and her newest title, “Container Gardening Complete.” Her website is jessicawalliser.com. Send your gardening or landscaping questions to [email protected] or The Good Earth, 622 Cabin Hill Drive, Greensburg, PA 15601.