Question
about half of my rose leaves are dying at the ends of the leaves. Blue black curly then green which then progresses to kill the leaf. What might be causing this. Located in the high mountains of the Southwest in a dry climate.

Answer
Did you have a cold snap just before the leaves started to grow? This will cause what you describe. The leaves were damaged even before they grew. A fertilizer can also cause tips to die as it can burn them where they are tender and new. Downey mildew makes the leaves curl and gradually kills them. A mixture of 1 tablespoon baking soda to 1 quart of water sprayed daily on the leaves until they new ones are healthy, will solve the mildew problem. The roses, if they have any these problems, will start growing healthy leaves in a couple of weeks time.