How naive I was, taking so much care when planting and nurturing those first little  stachys affinis rhizomes! Now I find that it is in fact a thug of a plant, a member of the mint family and ferociously invasive. So yesterday I spent several hours grovelling on my knees forking out the spreading plague. I plan to replant some of them in a container as they can create a nice gastronomic flourish, although very fiddly to prepare. I guess some of the little devils will have escaped, but the bed is now looking clear and the elephant garlic it was suffocating now free to grow on unimpeded.