Soapwort

Also known as "Bouncing Bett" or Saponaria officinalis. Boiling in water produces a greenish lathery detergent which can lift grease and dirt. It was used in Britain by medieval fullers to clean and thicken the cloth and has also been used in modern times for delicate fabrics such as old tapestries. Richard Mabey (in "Flora Britannica") says it was used on the natural silk produced by Hart-Dyke that was used for royal wedding dresses. Also by the Victoria & Albert for cleaning fragile fabrics and by the National Trust for cleaning antique curtains. A lot of the plants in the wild probably result from garden throw-outs but colonies near old mills probably result from use in industry. And Richard thinks that a mass growing (pre-development) outside the churchyard of St Winnow by the River Fowey was probably used for washing church vestments. He thinks the name "bouncing bett" has to do with it's associate with washerwomen although I don't quite follow.