I think the pink type of Knock Out is less disease resistant than the regular cherry red colored type. But it still has some decent resistance. The rain certainly contributed to the problem but crowding plants or anything that reduces air circulation also contributes to foliar disease problems. I would feed them lightly now as they won't be growing a lot in the cooler weather but in your warm winter climate will still remain leafy for quite a bit of the cool winter season. Then in March start feeding them again periodically on through summer. A fertilizer with a 3-1-2 ratio, such as 15-5-10 or 21-7-14 is fine since your soils typically have plenty of phosphorus in that area. Sprinkle 1/4 cup of fertilizer evenly through out a circular area around each bush when you feed. For this current feeding I might go with just a little less.
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