Saponaria ocymoides. Height to 10-40cm (4-16"). Rock Soapwort is a favourite perennial for alpine and rock gardens. This semi-evergreen blooms from May to August with five-petaled pink flowers joined at the base to form a nectar tube that is highly attractive to bees. Provide good drainage. Try planting spring flowering bulbs beneath it so that their flowers and foliage rise above. The roots really can be used to make soap. Rock Soapwort looks marvelous in containers, but best in situations when it can trail and seed itself. Plant it in rock trough gardens to to grow on a rock wall.