14 common garden invaders and the best ways to control them
Pull young plants in spring, before they develop a perennial root system. To kill established clumps, repeatedly prune back the stems as they sprout; this eventually exhausts the roots. Or mow the tops and dig out the roots; repeat the process as new canes grow from roots left behind.
You can also cut stems to the ground and apply glyphosate to the stubs as soon as possible after cutting. Spot-treat any new shoots with glyphosate as they appear.