Crepe Myrtle — Your Questions Answered

July 10, 2009 | By | Comments (312)

Crepe myrtles are hot right now. In fact, no subject is of more interest to Southerners this summer, not even the stirring Presidential campaign of Ron Paul.

Thus, the ever-generous, all-caring Grump will answer 10 of the most common questions about crepe myrtles directed his way every week.

Crepe

 

1. What does crepe myrtle need to grow well and bloom?

Answer — Lots of sun, well-drained soil, and extended summer heat. After suffering for so many years from hearing about how great gardening is in England, I am gratified to know that crepe myrtle hates it there. The summers aren’t sufficiently long and hot.

Winter cold is another consideration for you people up north. Although some selections, such as ‘Acoma’ (white), ‘Centennial Spirit’ (dark red), ‘Comanche’ (coral pink), ‘Hopi’ (medium pink), ‘Yuma’ (lavender), and ‘Zuni’ (lavender), are reputed to withstand temperatures below zero, if zero temps are common where you live, I wouldn’t plant crepe myrtle. It does best in Zones 7, 8, and 9. Instead, plant ‘Pink Diamond’ or ‘Tardiva’ hydrangea. (Both are selections of summer-flowering Hydrangea paniculata.)

2. When is a good time to plant crepe myrtle?

Answer — When the plant is dormant, either in fall, winter (where winters are mild), or early spring. Of course, you can plant a crepe myrtle grown in a container in summer too, as long as you water it frequently to keep it from wilting. Once it’s established, it’s quite drought-tolerant.

3. When should I prune crepe myrtle?

Answer — Late winter is the best time for two reasons. One, the plant has no leaves, so you can easily see all the branches and which ones need removing. Two, crepe myrtle blooms on new growth. Pruning in winter won’t reduce summer blooming.

Having said that, you can produce a second major flush of blooms on most crepe myrtles by pruning off the round, green seed pods that form just after the first flowers fade. The second flush won’t be quite as showy, but you’ll like it nonetheless.

4. What is “crepe murder?”

Answer — Crepe murder is the odious practice of using saws and loppers to cut down a crepe myrtle into thick, ugly stubs, usually performed on an early spring weekend by bored husbands seeking to justify their existence to women. This ruins the natural form of the plant, produces weak spindly branches too weak to hold up the flowers, and prevents the formation of the beautiful, smooth, mottled bark that looks so pretty in winter.

For specific instructions on pruning crepe myrtles, see “Stop! Don’t Chop” and “Crepe Myrtle Pruning Step-by-Step,” two highly informative articles written by your favorite Grump.

5. What’s that black stuff all over the leaves?

Answer — Hershey’s Dark Chocolate. Nah, just kidding. Actually, it’s black mold growing on the sticky honeydew produced by sucking insects, usually aphids. Get rid of the aphids and you’ll have no mold. Spray according to label directions with an environmentally friendly product, such as refined horticultural oil on insecticidal soap (make sure to wet the undersides of the leaves), or a systemic insecticide that’s absorbed into the leaves, such as Ortho Max Tree & Shrub Insect Control.

6. White that’s white stuff all over the leaves and flower buds?

Answer — Powdery mildew, a fungus that likes warm, humid weather. Many older types of crepe myrtle are highly susceptible. The fungus distorts the foliage and often ruins the flower buds. While you can prevent powdery mildew by spraying according to label directions with a fungicide such as Daconil or Immunox or even with refined horticultural oil, you’re better off buying a mildew-resistant selection, such as ‘Natchez,’ ‘Miami,’ ‘Sioux,’ ‘Dynamite,’ and ‘Biloxi.’ Look for this on the plant label.

7. Why doesn’t my healthy crepe myrtle bloom?

Answer — Could be lots of reasons. Maybe it doesn’t get enough sun. Maybe powdery mildew ruined the blooms. Maybe Japanese beetles ate it. Maybe it just needs a few more years to grow. Maybe you’re in a drought. A crepe myrtle will often go dormant during a very dry summer with flower buds ready to pop. They’ll only pop when the plant gets some water, either from rain or from you.

8. What are some crepe myrtles that don’t get so tall?

Answer — One way to avoid crepe murder is to select varieties that don’t need pruning. Small ones (5-10 feet) include  ‘Acoma,’ (white), ‘Hopi’ (pink), ‘Tonto’ (red), and ‘Zuni’ (lavender). Dwarf types (3-5 feet) include ‘Centennial’ (purple), ‘Petite’ (various colors), ‘Razzle Dazzle’ (various colors), ‘Pocomoke’ (rose-pink), and ‘Victor’ (deep red).

9. What are the Grump’s favorite crepe myrtles?

Answer — ‘Natchez,’ (tall white), ‘Miami’ (tall pink, pictured above), ‘Catawba’ (medium purple), ‘Dynamite’ (medium red), ‘Watermelon Red’ (tall red), ‘Petite Orchid’ (dwarf purple).

10. Why do you spell crepe myrtle with an “e”?

Answer — It never ceases to amaze me how many people think this spelling is the most significant issue facing the world today. I spell it with an “e” because the crinkled flowers remind me of crepe. If you want to spell it “crape,” go ahead — on your own blog.

COMMENTS

  1. randy from texas

    i have 5 natchez crepe trees that i planted 6-12 in zone 10a south texas. They appear to look health but i don’t have any new buds yet. i have noticed other crepe’s in this area are leafing out. they did very well last year even though i planted in the hottest time of the year. all the crepe’s are in full sun all day. can you help explain.

    March 19, 2013 at 1:11 pm
  2. Steve Bender

    Randy,
    Not to worry! There are lots of different crepes and they behave a little differently. If yours are healthy, they should be leafing out shortly. Now if they still haven’t leafed out a month from now, start worrying.

    March 29, 2013 at 10:05 am
  3. Garry

    I have several cr’s but for some reason one starts to quit blooming and the leaves start to die, no bugs, no visible signs of anything. In the spring around May the new growth comes with beautiful flowers and leaves. Then somewhere around late July, in the top third of the bush, the buds appear and never open. The leaves wither and die. New growth begins in the lower third of the shrub, which is abour 5-6 feet tall. Everything is starting to pop now but I know what will happen come July. I live in El Paso texas. I have watered, not watered, fertilized with acid, not fertilized. Nothing seems to help.

    April 16, 2013 at 6:21 pm
  4. Brenda

    How do you start crepes from an old one thats big and beautiful……….Brenda fm Pittsburgh

    April 17, 2013 at 9:56 am
  5. Steve Bender

    Garry,

    I’m betting the problem is a fungus called powdery mildew that looks like a white film on leaves and flower buds. Flower buds that get it don’t open. You can prevent mildew by spraying according to label directions with neem oil, horticultural oil, or Immunox.

    Brenda,

    Crepe myrtles are easy to grow from seed. I’ll bet you have seedlings all around. You can also root a cutting. Take a 6-inch tip cutting (without flowers) in June, strip of the lowest set of leaves, dip the cut end in rooting powder, and stick the cutting in a pot filled with moist potting soil. Keep the soil moist and the pot in shade. Rooting should happen in about a month.

    April 22, 2013 at 12:53 pm
  6. Gayle

    We have 3 CM, live in St. George, UT and they have less than 2 leaves each. All over the community the other CM have all leafed out, we’ve watered and fertilized – any suggestions?

    April 22, 2013 at 11:22 pm
  7. Steve Bender

    Gayle,

    Are these new crepe myrtles? Sometimes new ones start later. The best advice I can give is give them some TLC, but don’t fertilize again until they are actively growing.

    April 24, 2013 at 8:43 am
  8. Gayle

    Thanks for the reply. Our crepe myrtles are not exactly new, about 4 years old and last year they budded and bloomed right along with all the rest but definitely not this year.

    April 24, 2013 at 8:36 pm
  9. Sandy

    I just moved to the Atlanta area from the NE. We have a beautiful crepe myrtle in the front yard. It has multiple thin stems growing up around the base of the trunk. Can I use these to root and plant more trees? How and when? Thanks for any input. I love southern plants and am looking forward to more gardening!

    April 27, 2013 at 8:31 am
  10. Steve Bender

    Sandy,

    While it is possible to use a sharp spade to separate a sucker from the mother plant, keep in mind that any time you cut crepe myrtle roots, they send up lots of suckers.

    April 29, 2013 at 2:09 pm
  11. F. Stanley

    Stores here in Kansas City are selling Black DIamond crepemyrtles, is this a good specimen for this area? There is very little information with this shrub.

    May 1, 2013 at 10:07 am
  12. Steve Bender

    My information is that ‘Black Diamond’ is an illegal release by someone who didn’t own the patent. That’s why you can’t find any info about it. I can’t say whether it’ll be hardy in Kansas City, because apparently nobody knows.

    May 8, 2013 at 10:53 am