Rock Cress 50+ Fresh Seeds Gorgeous Cascading Blue Rockcress Beautiful Cascading Blue Rockcress 50+ Seeds. Fresh for 2015 planting. Gorgeous! Nice for Ground Cover, Walls, Cracks in Walls or Steps. Wonderful in Hanging Planters, Hills, Rock Gardens. These beauties like full sun or mostly sunny. Germinate in 14 - 21 Days. Perennial. Thinly cover with 1/8" - 1/4" soil after danger of frost in well-drained soil. Grows to height - about 4"-6".