Wall rock cress is an outstanding spring-blooming groundcover for rock gardens, slopes, and dry, sunny spots.
Wall rock cress is an outstanding spring-blooming groundcover for rock gardens and dry, sunny spots in zones 4-7.
After blooming, wall rock cress sports gray-green leaves that keep their color throughout the year.
Credit: Peter Krumhardt
Both are members of the Brassicaceae family which includescabbage,broccoli,Brussels sprouts, andmustard.
Both are early spring-blooming perennials that bear striking pink, purple, or white flowers.
But wall rock cress is less common than common rock cress and has larger foliage.
Credit: Peter Krumhardt
Wall rock cress and common rock cress also share similarities withwallflower(Erysimumspp.
), a spring and summer-blooming perennial in zones 3-10.
Use combinations of the three related plants to create vibrant bursts of color across otherwise tough landscapes.
Credit: Denny Schrock
Its low-growing nature makes it an excellent choice for planting along paths and walkways.
Or, when planted on a slope or green roof, wall rockcress blends seamlessly into landscape.
It also works beautifully in containers or as anedging plantat the front of a garden border.
Transfer the plant from the container to the hole but avoid overhandling the roots.
Backfill the hole with the displaced soil and tamp the soil down firmly.
If planting more than one wall rock cress plant, place them 12 to 18 inches apart.
Water well and keep the plants moist as they establish themselves (twice weekly in dry weather).
The evergreen perennial makes a great ground cover and grows easily in the crevices between rocks.
It also attracts early-season pollinators, including bees and butterflies, to spring landscapes.
Nancy Rotenberg.
Light
In a sunny spot, this perennial is practically carefree.
Wall rock cress demandsfull sunat least eight hours of direct light per day.
This makes wall rock cress an ideal pick for neutral to slightly acidic gardens with sandy or gravelly soil.
If your soil has ahigh clay content, plant wall rock cress in a container or raised bed.
Wall rock cress, like other rock garden plants, is drought tolerant.
Water new plants regularly (once daily for 2 to 3 weeks) in dry weather.
Once established, wall rock cress plants need watering only when the soil is dry.
The evergreen perennial prefers temperatures between 40 and 90 Fahrenheit and dry to moderate humidity.
In areas that experience hot, humid summers, the plant tends to languish.
Prolonged exposure to high temperatures may kill the plant.
Apply it early in the growing season when the foliage is dry.
Brush excess fertilizer off the foliage to prevent fertilizer burn.
Pruning
After flowering, cut your wall rock cress back by half to encourage bushier new growth.
This practice will also reduce the likelihood of leggy bare patchesa common occurrence for aging wall rock cress plants.
Potting and Repotting
Wall rock cress is great forcontainers in sunny locations.
Use a pot with ample drainage and fill it with a well-drainingsucculent potting mix.
Add the plant and secure it by tamping the soil around the root ball.
Water your wall rock cress regularly and deeply throughout the establishment phase.
Once established, water the plant whenever the soil feels dry.
Apply a balanced, slow-release fertilizer once annually at the beginning of the growing season.
As the plant grows, it will fill the container and maybe even cascade over the side.
Once blooming is finished, cut the plant back by half to maintain lush, compact growth.
Plan to repot or divide your container-grown wall rock cress every 2 to 3 years.
Begin by watering the plant to help ease the roots from the pot.
Place the plant in a new container filled with fresh succulent potting mix.
Divide your wall rock cress every 2 to 3 years in the spring or fall.
Replant the divisions approximately 12 to 18 inches apart.
Water the cutting well.
Place the container in a cool place (50 to 60 Fahrenheit) out of direct sunlight.
Keep the soil evenly moist until the cutting takes root.
Scatter your wall rock cress seeds on top of the soil and gently press them in approximately 1/8 inch.
It grows 6 to 8 inches tall in zones 3-9.
As temperatures rise, the lightly scented flowers fade to a paler pink.
Rosabella grows low and dense, typically reaching only 5 or 6 inches at maturity in zones 4-7.
It also features evergreen foliage with oblong, toothed grey-green leaves.
It typically grows in a dense mat just 4 to 6 inches tall in zones 4-8.
The rest of the year, the evergreen perennial features a dense mat of gray-green foliage.
It grows 6 to 8 inches tall in zones 4-8.
The mounding groundcover grows 6 to 8 inches tall in zones 3-7.
Creeping phlox thrives in full sun and neutral to slightly acidic soil.
It is drought-tolerant once established and needs little extra care besides a post-frost trim.
It seldom tops 6 inches tall and is hardy in zones 3-8.
Dianthus
Dianthus(a.k.a.
They offer a stunning contrast to the stark white blossoms of most wall rock cress cultivars.
Dianthus requires little care when planted in full sun and well-drained,neutral to slightly alkaline soil.
Like wall rock cress, dianthus won’t tolerate overly wet soil.
So, let it dry out between waterings.
In fact, they occasionally show up while snow is still on the ground.
The most common variety,Chionodoxa forbesii, features blooms with a striking white center and blue-tipped petals.
It is hardy in zones 3-8.
Like its familial counterpart, it prefers full sun and well-drained soil.
But unlike wall rock cress, common rock cress blooms come in vibrant shades of pink and purple.
So, plant them together to create alternating clouds of pink, purple, and white.
Wallflower
It’s hard to talk about rock cress and wall rock cress without also consideringwallflowers.
Wallflower is a short-livedperennial or biennialthat prefers full sun and well-drained soil.
Frequently Asked Questions
No.
Wall rock cress is not classified as invasive, but can grow and spread aggressively in favorable conditions.
To control its spread, cut the plants back by half after blooming and regularly divide existing plants.
For pathway plantings, look forsomething sturdierlikecreeping phlox,Irish moss, orsedum.
