Why Are There Rough Warty Growths on My Raspberry Canes?

Rough, warty, irregular growths on raspberry canes at or below soil level — or on the roots themselves — are almost certainly crown gall, caused by the soil bacterium Agrobacterium tumefaciens. The bacterium enters through wounds in the plant tissue (damage from cultivation, insects or frost) and causes uncontrolled cell division, forming the distinctive gall tissue. Crown gall is present in many soils and affects a wide range of woody plants. It looks alarming but its impact on established raspberries depends on the size and location of the galls.

Does crown gall kill raspberry plants?

Small galls on secondary roots or low on canes often cause little practical harm — the plant continues to grow and produce. Large galls encircling the main crown or the base of canes can restrict water and nutrient flow and cause progressive decline in cane vigour. If the gall is extensive and the affected plant is visibly declining, removal is the best course of action. Plants with only minor galling may continue productively for several years.

Managing crown gall in the row

There is no chemical control. Remove severely affected plants along with as much root material as possible to reduce the bacterial load in the soil. Avoid wounding roots and canes during cultivation — wounds are the entry points. The bacterium persists in soil for years, so replanting susceptible species in the same spot should be delayed. When replanting raspberries in a gall-affected area, choose certified planting stock and minimise soil disturbance.

Prevention for new plantings

Purchase only certified, disease-free canes from reputable suppliers. Do not replant from a gall-affected row. Avoid sites with a history of crown gall in other plants. Handle bare-root canes carefully to avoid unnecessary wounding at planting.