Wall Rockcress (Arabis caucasica) is also called Caucasian rockcress. This is a very dainty herbaceous plant with white flowers all over it. It is very good draped over a wall or planted in front of a garden as a garden border. It is native to the Mediterranean and Asia Minor.
Wall rockcress prefers full sun to grow in. It can tolerate drought conditions and can live in poor soils. However, it will not tolerate wet feet, so the drainage where it is planted must be good. Strive to keep the soil around wall rockcress moist but not soggy.
Wall rockcress lives in zones four to seven. It may be partially hardy in zone three, if in a sheltered place and covered with mulch to protect the roots. However, it dies of heat if grown in zones eight and above. Wall rockcress grows to one half to one foot and spreads from one foot to one and a half feet. It can form dense mats of leafy rosettes. It prefers slightly acidic soil, so mulching with pine needles is recommended to add some acidity to the soil.
Wall rockcress blooms during the late spring to the early summer. While almost all wall rockcress has white blossoms, some plants produce light pink flowers. The leaves are silvery green and are toothed. Wall rockcress is very fragrant. Wall rockcress is deer resistant.
Wall rockcress can be propagated by seed, cuttings, and division. In the spring, cuttings root quickly and produce plants just like their parent tree. To propagate by division, dig up the plant in the fall or early spring and divide it up. You will need a sharp knife to cut through the roots and divide the plants. Finally, you can propagate wall rockcress by seed. However, it is much easier and more reliable to use cuttings to reproduce the tree. Seeds sometimes fail to germinate or produce a plant that looks nothing like the parent plant. However, they can be strewn outside after all danger of frost is past. Do not cover the seeds as they need light to germinate.
When planting wall rockcress plants, space them thirteen to eighteen inches apart. They will soon expand to fill in the gaps between them. A high nitrogen fertilizer can be applied when planting the wall rockcress. A high phosphorus fertilizer should be applied just after blooming.
Wall rockcress will bloom the second season after planting and every spring and summer after that. Regular pruning to remove the dead flowers will keep the plant healthy and looking nice.
In the spring after the plant has finished blooming, cut it back severely. This will encourage it to branch and produce many blooms. Never prune in the fall because you will prune all of next year’s leaves off.
Wall rockcress has trouble with aphids. Insecticidal soap can kill the aphids, but most be applied correctly to do so. The soap must cover every part of the plant, especially the underside of the leaves, where aphids like to hide.