By Donnetta Wilhelm, Colorado Master Gardener
Have you ever seen this in the garden? It is rose crown gall, caused by bacteria that enters through wounds, grafting, or insect damage. Galls on roses are generally found at the crown, just below the soil surface, or on the roots. The bacteria can spread through the soil, so control is difficult. Established, mature plants can tolerate the bacteria and can remain in the landscape but it can kill younger plants or those that are susceptible to the gall. Managing crown gall is best done through prevention: closely inspect new plants before planting, disinfect pruning tools after use on infected plants and avoid planting susceptible plants.