To escape the turmoil's of the world, "we should cultivate our gardens," said Voltaire. However, people in ancient times, had utilitarian, as well as recreational motives for gardening. There are plants growing in almost every region of the world that can be boiled with water to produce a soapy lather. There are, for example, several species of "Saponaria" commonly called "soapwort."
Even after people learned to make soap from an extract of wood ashes and hot fat, some of these soapworts continued to be cultivated in flower gardens. One hardy perennial soapwort, which grows to a height of 1 ½ feet with pale pink or white flowers, is known as the "Bouncing Bet." The name seems to have come from comments about a buxom laundress seen from the rear, vigorously scrubbing.
This saponaria is not well behaved in the garden as it self sows and spreads aggressively. However, you definitely should consider planting the better behaved, low growing saponaria "ocymoides," because it is a wonderful rock garden plant. In early summer it is covered with small rose pink flowers and is a good companion for white candy tuft (iberus) or yellow alyssum (aurinia).
It is reliably perennial in zones three thru eight, and can bloom for over a month. It droops gracefully on walls, terraces, and slopes. It also likes sun. It is native to the Cote D' Azur region of France, but is also a favorite in American gardens.