Question
sprinklerI live in So Texas, red dirt soil. I planted my knockout rose bush in spring of 2008 and now the lower leaves are turning yellow, not all of them but most, and then turn brown and crispy.  The top leaves seem to be OK but the bush is not filling out, getting sort of sparse in the lower part.  I put leaves around the base of plant and try to water only with hose so no sprinkler water touches leaves. It is now Sept and wonder what I should do.

Answer
Since roses have become a commercial product, many rose myths have been proven of no value. Water on the leaves is one of them. When it rains, the leaves of roses take up water. They do it much quicker than the roots do. Getting water on rose leaves doesn't cause any problems unless it is done when conditions for Black Spot are ideal. Your roses have gone under stress. Because of the questions I am getting, it sounds like Knock Out roses don't like high heat and  so they go into stress. Stress just means the rose roots have shut down until conditions get better for them.In most gardens because of the long summer, many roses don't look their best and have yellow leaves. I would take a trowel and dig down to see if the water is getting right down to the roots because it sounds like it isn't. Really water the roses well and I think you will see good new growth. Don't fertilize if it is hot as the roots won't be able take it up but do soak them very well.