Well, we've all heard this one - bindweed (along with couch grass, and ground elder) is nearly impossible to dig out of beds and borders because even the tiniest little piece will regrow.
So the question is: Does it really grow back from a tiny piece?
Exhibit A, m'lud: six pieces of really fresh, plump, bindweed root - in this case, Calystegia sepium or hedge bindweed, which is the one I deal with most commonly.
On the 5th July 2013, I cut two pieces each of 3", 1½" and ¾" - that's about 7.5cms, 4cms and 2cms for the modernists out there - and placed them in modules half-filled with fresh new compost:
On the 25th July, just over a fortnight later, this was the progress:
On the 9th August I decided the experiment was concluded, as the ones which were growing well were threatening to escape from the module tray (below) and although I am all in favour of experimentation, I'm not keen to encourage this particular plant!
On investigation, the non-growing large piece was still there,but had rotted:
And down the other end of the tray, when I scraped away the compost, the two short pieces were still there, complete, un-rotted, but not showing any signs of sprouting.
Interesting, isn't it? You could draw the conclusion that ¾" (2 cm) is just too small to be a sustainable root. But why did only one of the 3" pieces grow?
The whole point of the scientific method is that it is repeatable, so please go on and have a go yourselves, and do let me know the length of the smallest piece you have found to be successful at regrowth.
Here it was - bindweed on the left, ground elder on the right, all clearly labelled with the date, the size and the species, as I know just how easy it is to forget which one goes where... ask me how I know this....
... and to my surprise, all six failed to grow, and by spring of this year they had all rotted away to nothing.
I don't think that these two simple experiments are enough to draw any great conclusions, but it possibly does throw some doubt on the view that even tiny scraps of these two garden menaces are capable of regenerating themselves and reinfesting the ground.
Although that does not mean that I shall be any less thorough in digging out the wretched stuff!