How can I get rid of a wisteria?
Stefan says: You have an unusual problem in that you want to get rid of a wisteria. It was growing around a pergola in your garden but, unfortunately, the posts rotted so it had to come down around 18 months ago.
You dug out and cleared away as much of the roots as possible and planted a philadelphus. This year the wisteria is sprouting quite vigorously through and around the philadelphus and you want to know if there is anything you can do to kill the roots.
I know from experience that wisteria are surprisingly durable and the roots will continue to put up new growth for a long time after the plant has been cut down. If you treat the shoots several times with a weedkiller containing glyphosate, following the manufacturer’s directions, it should eradicate it. But be most careful not to spray your philadelphus or other plants nearby.