We have golden splash shrubs on our sidewalk and a small part of that shrubs show what seems to be crown galls. We cut off the affected stems, but concerned that they will spread to the rest of shrubs. What should we do?
Unfortunately crown gall can remain in the soil for two years, so you may not be rid of it for a while. Removing the affected stems as you did will probably slow the spread but not stop it. The only treatments are plant removal, or a biocontrol treatment option as mentioned in the second article below: