Why are my CORAL DRIFT ROSES thinning-out at the inside of the bushes? They are still throwing on new growth to the outer and upper portions of the plants and still producing blooms; however, the interior of some of the plants is beginning to look rather "ragged". I am afraid the plants are dying?????? What should I do? They are well-drained in amended soil; they receive enough water (and I don't think they are ever over-watered), and I fertilized in late spring with Jobe's Rose Fertilizer Spikes. I gave them a quick hosing of Ironite last week when I was greening up the grass...they received only one quick pass with the hose-sprayer.
Thanking you in advance for expert advice...