Leaf Tip Dieback in High-Altitude Roses: Frost, Fertilizer, or Mildew?

High mountain Southwest gardener: half of rose leaves dying at tips—blue-black curl, then green, progressing to kill leaf. Dry climate.

Possible Causes

• Cold snap before leaf-out damaged emerging leaves.
• Fertilizer burn on tender tips.
• Downy mildew (causes curling, gradual death).

Mildew Treatment

1 tablespoon baking soda per quart water, sprayed daily on leaves until new growth is healthy. Roses will push clean leaves in a couple of weeks regardless.