Crape Myrtles

Seasoned southern gardeners know that – while there are few hard-and-fast rules – you must have certain plants. Wilmington is home to the North Carolina Azalea Festival, so evergreen azaleas are a requirement. If you fail to do so the azalea police will eventually catch you. Camellias are the same even if the enforcement might be slightly less stringent. Buck this trend and you will be informed that Interstate 40 does have west-bound lanes that lead to the north-bound lanes of Interstate 95.
When the temperatures tickle the triple digits, it’s the time for another southern garden must-have to take center stage – crape myrtle. This summer superstar sports showy blooms in shades of pink, white, purple, lavender and red. Handle it right and you can have 3 months of color with minimal challenges beginning in late May and continuing through September.     Unknown-2

Choosing the Perfect Crape Myrtle
Crape myrtles come in a wide array of sizes ranging from dwarfs that remain at three feet to towering trees reaching 45 feet. The smart move is to choose a variety that is just the right size for its particular garden location. Unfortunately, this point is over ignored and large growers such as ‘Natchez’, ‘Fantasy’, ‘High Cotton’ (white flowers) and ‘Muskogee’ and ‘Biloxi’ (pink flowers) that ultimately grow to at least 30 feet are planted where a 15-foot plant is needed. This poor choice results in horrific pruning practices that are often called “crape murder”.
Check with your favorite garden retailer about varieties they recommend.Master gardener NHC logo3

Growing Crape Myrtle
Crape myrtles aren’t particularly fussy. Average soil that is well-drained but not terribly drought-prone and plenty of sun are all that’s required. Soil pH’s between 5.5 and 7.0 are acceptable but iron deficiencies will show up as you flirt with 7.0 and above.
While most crape myrtles are grown with 3 to 7 stems, you can find what nursery growers call a “standard”. That just means it has one main trunk. If you’re planting along a walkway or in a relatively formal garden like the Tribute Garden at the New Hanover County Arboretum where you need clearance for people to walk, the single-stem form makes sense. But, the picture of a crape myrtle in most people’s minds is multi-stemmed.
Plants, like children, should be trained when they are young and relatively easy to work with. That means setting the basic form and removing crossing limbs, suckers and basal sprouts.
But, the aforementioned “crape murder” is always a bad idea. Many people believe the plants bloom more after heavy pruning, but research proves that to be false. The result is weakly attached limbs that shear in a wind storm and plants that lose their natural beauty and form. Crape myrtles will tolerate it, but that doesn’t mean it’s a good thing.
Crape myrtle selections that bloom earlier in the season (June through early July) are easy to coax into a second bloom. As the flowers fade and form seeds, remove the clusters of seed pods and add a bit of nitrogen to support new growth. If the days are long enough and it’s still hot, you will be rewarded with lots of late-season color.

Problems with Crape Myrtle
Crape myrtle aphid, a light-green critter that clusters on the undersides of the leaves and drinks the sugary sap, is the most common insect pest. Leaves covered in shiny and sticky honeydew let you know the aphids are around. Left unchecked sooty mold will grow on the honeydew prompting the oft-asked question, “Why have my crape myrtles turned black?”
Check the undersides of the leaves as you walk through the garden for the aphids. And, learn to recognize the larvae and adults of lady beetles that are busy eating aphids and aphid eggs. This battle plays out on the ‘Osage’ (light pink flowers) in my garden each year. Sometimes the aphids finally win and I have to spray, but let them help you as long as you can. For those trying to avoid traditional pesticides, insecticidal soap works reasonably well if you cover the aphids with the spray solution. Traditional insecticides such as bifenthrin and acephate control the pesky critters but will remove the lady beetles in the process.
Powdery mildew, a fungal disease, distorts the new growth during cool weather in the spring. The best solution is to plant varieties with resistance including the many named for Native American tribes.
Cercospora leaf spot, another fungal disease, can cause leaf drop during warm, wet weather. It usually doesn’t warrant treatment with fungicides.
Clemson’s Cooperative Extension Service has an excellent publication at www.clemson.edu/extension/hgic/pests/pdf/hgic2002.pdf that discusses these problems in more detail.
For answers to your gardening questions visit http://ces.ncsu.edu, where you can post your questions via the ‘Ask an Expert’ link, or contact your local Cooperative Extension center Pender County  259-1238; New Hanover County  798-7660; Brunswick County 253-2610.

Al Hight, NHC Extension Director