Question
I set out 6 crepe myrle trees 2 years ago.  There virtually is not difference in size compared to now and then.  The soil is very hard-dry clay soil; however,I did dig out twice the size as the root ball and replace with good potting soil.  Besises fertilizing properly, what else is there to be done to cause growth or am I up the creek without a paddle?

Answer
Fertilizing would be the best thing for these.
A complete general-purpose garden fertilizer -- such as 8-8-8, 10-10-10, 12-4-8 or 16-4-8 -- is ideal for crape myrtle. To newly planted small plants (1-gallon size), apply 1 teaspoon of fertilizer monthly from March to August along the perimeter of the planting hole. Larger, established plants will benefit from one broadcast application of fertilizer in spring. Apply 8-8-8 or 10-10-10 at a rate of 1 lb. per 100 sq. ft. or 12-4-8 or 16-4-8 at a rate of ?lb. per 100 sq. ft. Avoid over-fertilization because it causes excess growth and reduced flowering. The best time to fertilize is just before a rain. Otherwise, water in the fertilizer after application with irrigation. It is not necessary to remove mulch when fertilizing.