I realize a lot of you may say, after reading this week's tip, "where was this information two months ago?" But never in my nearly 9 years of answering gardening questions have I heard so many querries about Crape Myrtles NOT BLOOMING, as I have this year. And so, I finally decided it was time for a tip sheet on the struggle of crape myrtle blooms this year.
Fortunately -- or unfortunately -- depending on your perspective, there are many reasons. Let me start by getting some of the obvious things out of the way. Possible reasons for lack of flowering include:
Excessive shade. Crape myrtles require 8 hours of full sun daily for optimum flowering.
Variety. Some varieties don’t flower as vigorously as others
Heavy aphid infestation. Aphids are common insect feeders on crape myrtles and can decrease flowering.
Lack of fertilization. Crape myrtles require fertilization for new growth. If new growth doesn’t occur in the spring (because of nutrient depletion or cold weather), flowering may be greatly reduced.
Improper pruning. Drastic pruning or pruning after new growth in the spring can delay summer flowering. Drastic pruning may promote excessive growth and less flowering.
Overfertilization. Excessive fertilization in conjunction with other factors, primarily improper pruning, can eliminate or delay flowering. Also, too much high nitrogen lawn food can cause excessive green growth and no bloom potential.
Leaf spot. (Also known as Cercospora) Foliar diseases decrease plant vigor and flowering, especially where new growth is not produced.
And it's not a joke, when I say that some of these crapes can and are suffering from a wicked combination of 2 to 3 of these issues. As an example, I've seen crape myrtles that I know were not pruned effectively in February, fed only lawn food in the spring, and covered with Aphids.
Take this list with you and let's find out what combination of problems have led to this year's weak blooming, and work to have better Crapes next year. Rememer these key issues:
Prune them only in January thru March
Feed them consistently with balanced food (ex: 1-2-1 ratios) or bloom enchancers (such as a super bloom 10-50-10).
Avoid putting lawn foods near the root systems (too much nitrogen, means only green growth and no blooms)
When signs of fungal disease hit, treat with Consan, Kocide, or Banner-based fungicides.
If you see insects, like Aphids or Whiteflies, you have to treat every 5-7 days with a liquid insecticide until you are convinced you have solved the problem -- one application will never suffice.
Until next issue, here's to
Great Gardening from the GardenLine, heard
exclusively weekend mornings from 8 to noon
on Talkradio 950 KPRC.
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