Dig deep to win the war on weeds
The way to keep nuisance weeds at bay is to wear them down, says Tom Petherick
Gardens all over the country are struggling against the onslaught of a number of pernicious weeds that appear to be going from strength to strength. Old foes Japanese knotweed and Rhododendron ponticum have been joined by two heavyweights in the form of hemlock water dropwort ( Oenanthe crocata) and Himalayan balsam ( Impatiens glandulifera).
Lesser lights such as Carex pendula, horsetail and tuberousrooted oxalis must also be counted as nuisance weeds because they spread quickly and are difficult to shift.
These weeds have always been with us, it is simply that conditions have become ripe for their spread. It could be that increasingly warm and wet winters are a significant factor in their success. John Lanyon, garden manager for the National Trust at Trelissick in Cornwall predicts a day when hybridisation of weeds with garden plants might even lead to a super-weed.
At a moment when the use of the weed killer Roundup (active ingredient glyphosate) is under scrutiny it is useful to look at other ways of dealing with weed problems.
While the hemlock and balsam are weeds of grassland and waterway, the others can make life in the garden extremely difficult. They join a long list of old foes such as docks, dandelions and ground elder as dominant perennial weeds.
In rural Devon, where I live, the rise of has been singular. I see it all over the West Country now – and not only by waterways.
A native of the UK, it is perennial but also an efficient self-seeder, rapidly invading grassland, woodland and any unattended areas. It should be treated with extreme prejudice as it is highly toxic. Ingestion of the roots is fatal to humans and livestock. It has made it to gardens everywhere, and unless