THE pink-flowered soapwort has been flowering by roadsides in many parts of the country, mainly the east, for a few weeks now. This is an eye-catching plant because of its soft pink colour, a shade not often seen in a wild hedgerow. It is not often seen because it is not a native species, but a garden escape.
A 'garden escape' is a plant that is, or was, cultivated in gardens but has made its way into the wider environment. Soapwort is botanically called Saponaria officinalis, the first part meaning soap-maker and the second a reference to its use as a herbal remedy for skin and respiratory ailments. Wort is an old word for a plant, often a plant that had a practical use, or was used medicinally.
Saponaria contains a group of chemicals called saponins, which are soap-like in action, and can be five per cent or more of the plant's weight. These are used by the plant as poisons to prevent grazing, and no grazing animal will touch this plant, including deer or rabbits.
The saponins can be released by chopping up the leaves or roots and boiling them in water. When the boiled leaves or roots are removed, the remaining strained liquor can be used as a gentle soap or shampoo, and since ancient times for washing wool.
Despite being potentially poisonous, it has also been used in small amounts to put a foamy head on beer, and occasionally in the making of the sweet halva.
Related to carnations, soapwort normally has five flat petals. The species seen by roadsides is almost always double-flowered with more than five petals, a sure sign that it is a cultivated plant that has escaped. Although it is invasive, it can be grown quite happily in a semi-wild corner in sunshine or part-day shade.
There are a few species that are much smaller and generally grown in rock gardens, making a broad mat of foliage and flowers in summer, notably Saponaria ocymoides. These are very pretty small plants, easily grown in well-drained soil, not overly fertile.
The taller soapwort is rarely seen for sale as it can be a runner, but, if desired, it is easily raised from cuttings of the stem in summer, even while flowering, and from divisions, or just pieces of the roots in autumn or winter.
It is very weed-resistant, well able to cope with competition from weeds or grass, a durable, long-lived plant with pretty flowers and a sweet light scent.