Ask the Master Gardeners: Crape myrtle blossom colors can depend on sun exposure

By: Laurie Meyerpeter, Placer County Master Gardener
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Question: I bought a red crape myrtle two years ago and this year when it bloomed the blossoms aren’t red, they’re deep pink. I wanted the red variety that I see planted in my neighborhood. Did I get the wrong variety? Was it mislabeled? Or did I do something wrong? Answer: There are several new red crape myrtles on the market. Previously “red” crape myrtles were a deep magenta-red. In recent years several true red crape myrtles have been introduced. Two widely available varieties include the hugely popular “Dynamite” and the newer “Red Rocket.” “Dynamite” has bronzy red foliage, gorgeous fire-engine-red blossoms, and turns orange-red in the fall. It has a stiff upright shape when young and seems to have a slightly slower growth rate than other crape myrtles. “Red Rocket” has cherry red blossoms, good fall color and an upright rounded shape. It appears to be slightly more vigorous than “Dynamite” as well as being a repeat bloomer. It is likely that “Dynamite” is the tree that you saw, or if it is a young tree, “Red Rocket.” The main cause of red crape myrtles with pink blossoms instead of red flowers is insufficient sunlight as the buds are developing. Crape myrtles like full sun. Strong sunshine is even more crucial for the red cultivars. A second but related cause is overcast or cloudy days during blossom development. In 2008, many red crape myrtles produced pinkish-red blossoms in this area because of the heavy smoke pall caused by the many fires of that year at a critical stage in blossom development. In addition to pink blossoms, red crape myrtles will sometimes produce white petals. These are also caused by not enough sun. Although the resulting blossoms can be quite attractive with red, pink and white flecked flowers, this is not desirable and reflects a lack of sufficient light. The Master Gardener hotline is (530) 889-7388.