Generally, when the bottom of the leaves of a rose turn brown, it is a symptom of a spider mite infestation. If you want to double check, just put a clean white piece of paper under the leaves and tap them. When you look at the paper you can see tiny, itty-bitty, dots. Those are spider mites.

It's a good practice to wash the underside the the leaves of your roses with a water wand periodically to avoid spider mites.

Smiles,

Lyn
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