- Name also: Bouncingbet (USA)
- Family: Pink Family – Caryophyllaceae
- Growing form: Perennial herb. Rhizomatous. Forms stands.
- Height: 30–90 cm (12–35 in.). Stem sturdy, usually glabrous, sometimes finely haired.
- Flower: Corolla regular (actinomorphic), pink–lilac–white, 2.5–3.5 cm (1–1.4 in.) broad; petals 5 or many, entire, with notched or ragged tips. Corona small. Calyx narrowly round, 5-lobed, violet, without epicalyx. Stamens usually 10. Pistil of 2 fused carpels, styles 2. Inflorescence a dense, 2-sided cyme. Flowers with pleasant fragrance.
- Leaves: Opposite, lower short-stalked, upper stalkless. Blade elliptic–elliptically ovate, with entire margins, 3-veined.
- Fruit: 4-valved capsule.
- Habitat: Sites of old houses, gardens, banks, wasteland, rubbish tips. An ornamental, escape from cultivation.
- Flowering time: July–September.
Soapwort grows ferally in southern and central Europe. In Finland its cultivation was promoted in the 18th century during the time of utilitarianism, which aimed to e.g. breathe new life into the use of old, useful plants. Soapwort’s roots contain a lot of saponins which makes it good for washing woollen clothes, shorn sheep and also hair. Soapwort was used as a medicine to treat e.g. liver disease and coughs and even used to give beer a better head. Internal use was however abandoned because the saponins are toxic: they have a detrimental effect on red blood cells by destroying haemoglobin (haemolysis).
Soapwort spreads with the help of its thick rhizome, easily striking out in new directions. Parts of the rhizome can also end up in the wild with other garden refuse and start to grow there. Soapwort grows nowadays as a leftover from cultivation in many places in southern Finland including old dwelling sites, gardens that have gone wild and roadsides. It grows most commonly in south-western Finland but it can be found as far north as Northern Ostrobothnia. Soapwort thrives well in the Finnish climate, doesn’t mind being cut down, and hangs on tenaciously in its growing place, even for decades, without any care. Soapwort isn’t very demanding with regards to habitat, although it favours loamy, calciferous moraine land.
Soapwort is also cultivated to a certain extent as an ornamental, although nowadays other perennials have nudged this native plant into the background. There are varieties with white and reddish flowers and also with a compound cyme –which is regarded as more beautiful comes down to a matter of taste. Its flowers have an irresistible fragrance, which spreads especially well in the evening. It is no wonder that soapwort is one of the best butterfly plants, especially for hawk moths and moths. It is at its best in a traditional bed beside a wall, from where its fragrance can fill the whole yard and inside the house too.
In Finland rock soapwort (also called Tumpling Ted) is an ornamental just like soapworts most often, but it cannot be found in the wilds as often. Rock soapwort is lax and clearly smaller than soapwort. Also flowers (less than 1 cm) and leaves (less than 3 cm) are smaller. Flowers are pink or white and fragrant.