Gray scaly bark on Crape Myrtle

Question from Jonnie:
My crepe myrtle was purchased with a gray scaly bark = it looks like fungus.  What organic spray can I use to rid the plant of this fungus. What kind of soil would you use to put in ground for the crepes?

Answer from Pat:
Without seeing your crape myrtle (Lagestroemia indica) or a photo of the bark I cannot tell if there is anything wrong with it. However, though it may look a bit messy now, most likely nothing is amiss. People plant crape myrtles not only for their spectacular summer flowers but also for their interesting mottled gray, taupe, pink and fawn bark. Like sycamores, the bark of crape myrtle does not stretch or become furrowed as most tree bark does. Instead, as the tree grows its bark peels off in patches, revealing the new pink bark beneath. This mottled look is actually one of this tree’s most interesting characteristics.
With this tree you get a triple whammy: spectacular fall flowers, fall leaf color, and handsome bark that is especially
attractive in winter after leaves fall.

Crape myrtles grow best in interior climate zones where summers are hot and dry. They do not like water-logged
soil and perform best in well-drained soil with deep but infrequent irrigation, and light pruning in late winter or early spring to encourage new growth for summer bloom. Crape myrtle blooms on new wood. Letting the tree go slightly dry in late summer and withholding summer fertilizer will increase the display of blossoms in late summer and early fall. It is not a good idea to plant this tree in a lawn.

Crape myrtles are not good choices for Sunset Zone 24 where coastal fog and June Gloom blankets gardens in moist air. In such conditions crape myrtles tend to succumb to mildew. Mildew doesn’t affect the trunk. It affects the leaves and sometimes also the flowers. The general guidance for planting all trees is to plant them straight into unamended native soil, since the tree will eventually have to grow there anyway. That said, crape myrtles thrive best in soil that is well drained. Gardeners who plant them in heavy clay soil would be wise to provide a raised bed.

Such a bed does not need to be very high. Even four inches will save the crown of the tree from becoming water-logged. Fill the raised bed with good quality top soil mixed with nutrients and well-composted organic matter, but before doing so apply gypsum liberally to the native soil. Next dig some of your fill into the hard ground below, to create a marriage of soils instead of a hard line between the two. Then dig the planting hole straight through the top soil and mixed soil into the native soil beneath. Add more gypsum in the bottom of the hole and some slow release organic fertilizer in the bottom of the planting hole. Then plant the tree and refill the hole. Make a watering basin and keep the roots well watered until established then gradually lengthen out the times between irrigations.