Have you been awed by the lovely crape myrtles flowering in our Napa Valley neighborhoods lately? If so, you may have wondered whether these beautiful trees and shrubs would thrive in your garden. Are they difficult to grow and maintain? How much sun, water, fertilizer and care do they need?
Crape myrtles (Lagerstroemia) make great street trees because their height keeps them under power lines and their roots do not buckle sidewalks. (However, some cultivars can grow 100 feet tall.) They are also grown as shrubs in many gardens. They have many admirable attributes and are not difficult to grow or maintain in Napa County.
Indigenous to China, crape myrtle is not a true myrtle. The name is a nod to the leaf shape, which resembles that of a true myrtle. The ‘crape’ part of the name comes from the bright, colorful, crinkly, delicate petals that look as if they are made of crepe paper.
Their best features include the timing and length of their bloom. Crape myrtles start blooming in July and continue into October, peaking in August and September. They give our gardens a color boost when spring’s lushness fades and we are in the dog days of summer. Crape myrtles can flower for 100 days or more, making them among the longest-blooming trees and shrubs. Bloom color may be light or dark pink, lavender, white, dark purple or shades of red.
Crape myrtles also offer dramatic fall color as the leaves turn shades of yellow, peach, orange or red.
Even their bark is lovely. The branches and exfoliating bark of these deciduous trees stand out in winter. The bark’s multicolored, mottled appearance is especially beautiful in the rain. The old gray or light-brown bark peels off to reveal a smooth, polished, cinnamon-colored or pinkish inner bark. These giraffe-like patterns enhance the winter garden. (Ironically, some people panic when they notice their crape myrtles shedding bark, wrongly assuming that the tree is diseased.) Some people shape their crape myrtles as multi-trunked trees to get even more “oomph” from the bark display.
Crape myrtles attract beneficial insects and bees, and provide habitat for birds. Beneficial insects prey on garden pests, and honeybees fertilize our food crops. In light of our dwindling honeybee population, crape myrtles are a particularly good choice.
Crape myrtles are among the University of California at Davis’s Arboretum All-Stars because they are tough and easy to grow. University horticulturists recommend them as a substitute for thirstier trees because they can take a lot of sun without a lot of water. They do need regular watering the first couple of years, but once they are established, their water demand plummets.
You won’t need to prune much if you select the right crape myrtle for your space. If pruned too severely, a crape myrtle often responds with rank growth. Cutting branches back to stubs every year is not recommended. Better to prune too little than too much. Crape myrtles bloom on the current season’s growth, so they can be pruned in spring.
Scales and aphids can afflict crape myrtles, and the trees are susceptible to powdery mildew, although this is rarely a problem in Napa. In 10 years of caring for crape myrtles, I have never seen either pests or mildew on them. Selecting a mildew-resistant variety will also help you avoid this potential problem. The trees need only minimal fertilization. Too much fertilizer decreases flowering and encourages vegetative growth.
If you’re persuaded to add this lovely tree or shrub to your garden, buy it now while the trees are in bloom. Then you can be sure of getting your desired color. Pay attention to the branching, as each specimen is different.
The most popular crape myrtles are crosses between Lagerstroemia indica and L. fauriei or L. speciosa. They are sold by variety names, which include ‘Tuscarora’ (hot pink flowers); ‘Dynamite’ (deep reddish-pink flowers with bronze foliage); and the so-called Indian Tribe hybrids developed by the U. S. National Arboretum for resistance to powdery mildew. These have names such as ‘Cherokee’ (deep pink to almost red flowers) and ‘Seminole’ (medium pink flowers).
Determine the flower color you desire and the size appropriate for your site, and you will have a multitude of choices. Every summer, fall and winter you will be rewarded with a gorgeous display in your garden.
Vegetable Workshop: Napa County Master Gardeners will lead a workshop on “Cool Season Veggies” on Sunday, August 18, from 2 p.m. to 4 p.m. at the Yountville Community Center, 6516 Washington Street, Yountville. Grow your own vegetables even when days are short and nights are cold. The key is starting while weather and soil are still warm. Learn which vegetables will thrive in cooler temperatures, how to protect them from heat when they are getting started, and how to time plantings for months of harvest. $15 per person ($10 for Yountville residents). Register through Town of Yountville, Parks and Recreation: Mail in or Walk in registration (cash or check only). For additional information, call (707) 944-8712 or visit their web site.
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. Napa County Master Gardeners ( http://ucanr.org/ucmgnapa/) are available to answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to Noon, at the U. C. Cooperative Extension office, 1710 Soscol Avenue, Suite 4, Napa, 707-253-4143, or from outside City of Napa toll-free at 877-279-3065. Or e-mail your garden questions by following the guidelines on our web site. Click on Napa, then on Have Garden Questions?