Weedy corner: Enchanter's-nightshade

The Enchanter's deceptive charm...

You've got to admire Enchanter's-nightshade Circaea luteiana, which manages to insinuate itself unobtrusively among your mollycoddled treasures, quietly colonising an entire border – if you let it – before throwing up give-away sprays of tiny, pinkish-white flowers in July and August. By the time you notice these, the Enchanter has cast its spell and ensured that its brittle, waxy-looking, pure-white rhizomes are thoroughly entwined with the roots of all your most precious perennials.

This cunning weed has evolved so that it tends to break away at ground level if pulled up when in flower, leaving the stringy white rhizomes ready to launch a whole new onslaught of invaders. The only answer (short of giving up or resorting to chemicals) is to be patient and painstaking, using a hand-fork to trace back and extract every last bit of rhizome; not so difficult on our light loam, but a nightmare on heavier soils. As always, prevention is better than cure, and learning to recognise the young shoots in spring, then ruthlessly digging them out – rhizomes and all – as early as possible in the year, is far more effective than thrashing about in a mature border in late summer, doubtless inflicting colateral damage and generally using language unbecoming of an RHS card-holder.

The brittle white rhizomes are far-travelling...

Essentially a woodland plant, this 'nightshade' is actually a member of the willowherb family and more likely to be a problem in gardens where its preferred habitat of dryish summer shade and moist, well-lit conditions in spring are found. According to Richard Mabey in Flora Britannica, "No great powers or medicinal properties were ever claimed for it in this country", but 16th-century Parisian botanists considered this plant "...the charm that Homer's witch Circe used to turn Ulysses' crew into pigs".