Ground elder... The perennial weed that (along with bindweed and horsetail - both of which are very much at home in the garden, thank you), when he was asked on BBC Radio 4's Gardener's Question Time how to deal with them, prompted Bob Flowerdew to advise, "Move house!"
That option not viable, for the past three weeks, I 've been bottom up in a flower bed, grubbing up the tall green stalks (which had reached a rather unexpected 24 inches high) and long white stringy roots. It's given me plenty of time to consider the extraordinary properties of the clay soil in which they are buried and the relationship between them (but more of that below).
Now, after severe drenching (and I'm sorry, all this rain is obviously because I wielded a hose), it's thick and sticky, clinging like cake mixture to the gloves and hiding the roots in its glutinous grasp. Weedable, but not enjoyable.
Now, ground elder... My theory is that it hugs the heavy ground. It mats itself most in the areas where the soil's been left to its clayey ways. Those areas where I've piled on compost do see ground elder creeping in, but it seems not to advance with gusto and is much easier to keep on top of.
Of course, it could be that the improved areas are more visible and easier to weed anyway, so I'm removing a lot more than I think, but my theory is that it actually enjoys breaking up heavy soil. In New Age parlance, the presence of ground elder in clay is the soil healing itself, the roots strong enough to run through it, breaking it up, creating passages for air and water.
Too fanciful? Whether this is true or not, the remedy to this infestation (because we all know the ground elder will return. Oh, yes) is still to improve the soil. More organic matter, aerating the tiny clay particles, will keep it open in wet weather and less prone to imitating concrete in dry.
I'll be spreading a compost mulch and leaving it. Ground elder is often given as a reason not to adopt No-Dig gardening. But, as I surely know after the last few weeks, its roots mostly run no more than an inch or two below the soil's surface. The worms will draw in the mulch, creating a better soil, and the roots just lift out. It's actually quite fun. You can't beat the satisfaction of removing a root 24 inches long (it happens).
However, my theory (and I'd love to hear what others think of this) is that improved soil will also discourage ground elder because the weed will no longer be immersed in the heavy clay that it so obviously relishes.
That's my theory. You may call it wishful thinking.
March 2015: And here's an update on how I was getting on a couple of years later.