Posted: 21/05/2013 at 08:50
I had this plant too. It is very pretty but very invasive. I managed to find a spot where it could do it's thing but then waged war on the rest in the borders. Continue digging whatever you can but then dab the tiny new plants with glyphosphate as they emerge. I couldn't spray mine because it was growing through desirable plants but I found glyphosphate mixed with wallpaper paste & applied with rubber gloves and paintbrush worked well. I guess the new(ish) Roundup Gel that you can just dab on leaves would do the job just as well (wasn't available when I was waging war).
Important thing is to be vigilant & zap the new plants as soon as they have enough leaf to apply the Roundup or your potion of choice.
Good luck - I won the battle - you can too