Got a Rock Garden? Then, perennial Rock Cress plants are for you. Rock Cress flowers are native to rocky areas in the Mediterranean and Southern Europe. They were just too attractive to keep in one small area of the world. So today, you find it growing all over the U.S., and in other parts of the world, too. Growing Rock Cress is about as easy as it gets. They thrive in the slightly alkaline environment of rocky areas where other flowering plants struggle to survive. And, the plants do not need a lot of water or fertilizer. As a result, they are perfect as ground cover in many areas unsuitable for other plants.
Rock Cress produces a profusion of fragrant blooms in the spring. Colors are available in shades of white, pink, rose, mauve, and lavender. And Butterflies are attracted to the nectar-laden blooms.
Rock Cress find themselves at home in rock gardens, borders, edgings, and as ground cover. They are good for hills and slopes, where is it difficult to grow grass or other plants.
Flowers Bloom: Spring
Flower Colors: White, pink, rose, mauve, and lavender.
Plant Hardiness Zones: 4 – 9
Did you Know? The leaves and flowers of Rock Cress are edible, cooked, or raw. Not surprisingly, it has a pungent, cress-like flavor.
Perennial, Aubrieta Deltoidea
The plants are grown from seeds. They can be directly seeded into your flower garden, or seeded indoors for transplanting later.
For outdoor starts, sow Rock Cress seeds early in the season and cover lightly with 1/8″ of fine garden or potting soil.
The seeds have a long germination period, requiring two to three weeks. Sow seeds 6 to 8 weeks before transplanting seedlings outdoors.
Note: For indoor starts, we recommend a heated germination mat, to increase the speed of seed germination. Also, the germination rate is higher.
Keep soil moist during seed germination.
Established plants can be propagated by the division of the rootballs.
Ideal plant spacing is 15″ -18″. The plants spread out to form a loose mat, filling in the space between plants.
Days to Germination: 14 – 21 days.
Growing Rock Cress plants is easy. Grow the plants in full sun. Plants will tolerate light or partial shade.
They will do well in fair to poor, rocky soils, with a neutral to slightly alkaline pH. Sandy, loam, or clay soil is fine. It should be loose, well-draining.
Rock Cress likes slightly dry soil. Water only during the hottest, driest period of summer.
Add a general-purpose, high nitrogen fertilizer when first planting, to help them to get a good start. Add a high Phosphorous fertilizer just before blooming. Like with other plants, Phosphorous promotes blooms.
You need to have patience when first growing Rock Cress. The plants bloom in the spring of the second year after planting, and every year afterward. (They are worth the wait!)
Prune plant and remove dead flowers after blooms have died, to give the plant a clean, healthy look, and to promote new plant growth. See more on Deadheading Spent Blooms.
Rock Cress plants are hardy and will survive light frosts before going dormant for the winter months.
Ideal Soil pH: 5.5 – 7.0.
Plant Problems – Identify the causes and find the cures.
Rock Cress is seldom bothered by insects or disease. Apply insecticide or fungicide only if needed.