Knockout leaves turning yellow, then crispy brown and falling
I have 8 knockout roses and 2 katy road pinks that all seem to have the same problem. The lower half leaves turn yellow, then crispy brown and fall off. The roses continue to grow and bloom but I'm left with leggy, scraggly bushes. We've had an ongoing drought for 3 years now and it's very difficult with so little rain to feel my garden is watered well. I have clay soil also. I was told it was blackspot but the leaves don't get spots and various treatements for fungus haven't helped. The stem even gets yellow at the point of connection to the cane.