Saponaria officinalis aka Sweet Betty

Saponaria officinalis, also known as common soapwort, bouncing-bet, crow soap, wild sweet William, and soapweed, is a common perennial plant from the family Caryophyllaceae. Its scientific name is derived from the Latin word sapo, meaning "soap", due to the saponins found in the plant sap that produce a lather when in contact with water. These saponins are contained in the roots at levels up to 20 percent when the plant is flowering, making it useful for cleaning but also potentially toxic. The epithet officinalis indicates its medicinal functions. Soapwort is native to Europe and can be found as a horticultural escape and noxious invasive in much of North America. It grows in cool places at low or moderate elevations under hedgerows and along the shoulders of roadways. The plant is often seen growing along roadsides, waste places, and railroad tracks. It is a common host plant for some moth species, including the white-lined sphinx. However, as a weed, bouncingbet or soarpwort is on the Colorado noxious week list B and is required to be either eradicated, contained, or suppressed depending on the local level of infestation. It spreads rapidly and replaces plants of greater value, making it a nuisance to many gardeners.