Meet my nemesis: Convolvulus arvensis, commonly called field bindweed. I commonly call it something much, much worse.
Related to the lovely annual morning glory, field bindweed is a creeping perennial with roots that can penetrate up to 5 metres and produce more than 500 seeds per plant per year. If that doesn’t scare you, consider that bindweed seed can remain viable in soil for 30-50 years. It’s also drought tolerant, prefers heavy clay soils and can easily poke up through mulches because of its vigorous climbing habit.
A few years ago, I mistakenly ignored a small outbreak of bindweed between our gravel driveway and a cedar hedge. It quickly got out of hand as I worked on other more gratifying gardening projects and I now rue my lack of vigilance. Thank goodness there is the width of a gravel driveway between this thug and the front garden.
My penance is that I now spend more than an hour every two weeks throughout summer methodically snipping the stems at ground level when they reach 15 cm and discarding every morsel I remove. I cut, rather than pull the plants out, to avoid breaking roots underground. (It’s impossible to remove those long roots at one go!) Broken roots develop adventitious buds and shoots in just a few weeks which would only exacerbate this woeful situation. Sometimes more than two weeks elapse between my Bindweed Eradication Sessions (as the photo here testifies), but I am diligent about removing flowering vines before they set seed. In open areas, excluding light with a layer of black plastic for a year or two would thwart it, too.
Everything I’ve read says that if I keep up this regime for, oh, at least 3 or 4 years, the root reserves will decline as a result of reduced photosynthesis. I garden in hope.