I have two Burning bushes in my garden. They are full sized and grow quite well. However at the fall of the year they do not change their appearance to the red leaves that my neighbor enjoys just a short distance from mine (about 100 feet)tne plants are about 20 years old and have never turned totally red but do get slight color which never reaches full bloom. We live in northern Ohio where we see many such plants in full glory this time of year.They enjoy full sun and are well watered and have good soil. Anyone have a suggestion