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.
This perennial produces excellent, summer-long blooms on low growing plants that work well in containers and rock gardens.
When I Get My Seedling Home
Keep seedlings under very bright light to prevent legginess. Artificial lights are ideal, but a bright (ideally, south-facing) room will work for the short term. You may have to pot on seedlings more than once before they go out to allow for root growth. This is done by transplanting them into a slightly larger container with enough additional soil to keep the container mostly full. Keep the soil moist by daily watering and allow for free drainage so the plants are never sitting water.
Do not transplant outside until daytime temperatures are steadily 10°C (50°F) or warmer. This may mean keeping seedlings indoors for up to a month.
Transplant into dry, rocky soil in full sun or partial shade at 10-20cm (4-8”) apart. Water only during very dry spells, and do not fertilize. Cut back after blooming to keep plants compact. Saponaria plants do not transplant well, so be very gentle.