Crown gall is bacterial disease that infects and kills grapes, roses, fruit trees, shade trees, flowers and vegetables. Galls are rounded with rough surfaces and are made up of corky tissue. They can appear on stems near the soil line, on graft unions and on roots or branches. Don’t buy suspicious looking plants and don’t replant in an area where you have had crown gall. Avoid wounding stems, and disinfect tools between plants when pruning with hydrogen peroxide. Destroy infected plants or prune away galls.