Can anyone advise me on how to eradicate this weed which has completely overtaken the garden in our new house
Spray it with a solution of Glyphosate.Follow the instructions on the pack. Do it on a non windy day, as it will kill anything green. It will take a week or two to turn yellow and then die down. If it regrows, spray again in three weeks time.
Many thanks for that. Have you any idea what it's called?
I think it's Redshank, a type of Persicaria.
Persicaria campanulata. Mine was perfectly well behaved for the first 10 years or so. Then it spread a bit, so I split it and put some in a boggy hollow amongst trees, grandiosely known as 'The Dell'. That was the starting pistol. It was off!
It has spread across the entire space and I am now pulling it up and bagging it so it hs no chance to re-root. A little stream runs through the Dell, so I can't use weedkiller and I don't want it following the stream to pastures new!
I love it too - it's really pretty and colours up up better in sunshine, starts flowering early and goes on to the frosts. But like several other things here, once I've found something that will survive the conditions (right plant etc) it goes on to do too well.
I have that Geranium too, gorgeous colour and not too liberal with the seeds, but as it is a large plant, I now have too many of them. Same with Euphorbia Fireglow, Persicaria Taurus, a lovely dark red daylily called Mallard, Chelone Obliqua the Turtlehead,Campanula lactiflora, and just added to the list, Crocosmia Lucifer! With a large garden in a large landscape I like and need large plants, but I also want more than just the same half dozen wherever I look!