Read our guide to Arabis for everything you’ll ever need to know! Tips for planting & caring for Rock Cress.
Are you looking for a beautiful ornamental that will thrive in a wide range of environments? Arabis a.k.a Rock Cress is a great choice! Arabis is a large genus, with over 100 accepted species of flowering plants in the Brassicaceae family. The plants from this genus are native to several regions worldwide in North America, North Africa, Europe, and Asia. They are as beautiful as a picture – these plants show up with small, delicate, and cute flowers that fit very well with their distinctive foliage.
In general, most Arabis species go by the common name Rock Cress. There is no surprise that Rock Cress plants have won the hearts of many growers out there. While most Arabis species are weeds, some specimens enjoy lots of popularity as ornamental plants. The most common species in cultivation, however, are Arabis Caucasia (Garden Rock Cress) and Arabis Alpina.
Besides their bewitching nature, they are also super easy to grow and care for, even if you do not have much experience in the gardening world. Ready to learn more? Keep reading our guide to find out everything it is there to know about Arabis a.k.a. Rock Cress!
- Arabis plants belong to the Brassicaceae genus of plants which was formerly known as Cruciferae. This genus is often referred to as the genus of mustard flowering plants and it has many noteworthy edible members such as mustard, cabbage, broccoli, kale, Brussels sprouts, turnips, and ornamentals such as candytuft, honesty, and basket-of-gold.
- Although Arabis is a large genus of Old World and New World plants, recent studies have shown that these two groups are not each other’s closest relatives. Due to this, most of the New World members are now in the Boechera genus.
- Some of the most popular and good-looking Arabis species are A. aculeolata, A. alpina, A. arendsii, A. blepharophylla, A. caerulea, A. caucasia, A. glabra, A. hirsuta, A. lemmonii, A. macdonaldiana, A. procurrens, and A. pycnocarpa.
- Arabis Alpina ‘Flore Pleno’ and ‘Schneehaube’ are exceptionally attractive mat-forming plants and they have been awarded the Royal Horticultural Society Award of Garden Merit.
- Rock Cress plants thrive in a wide range of habitats, such as rocky mountains, cliff sides, open woods, dry sites, prairies, or streambanks.
- These beauties can be wonderful additions to different landscape decorations. Arabis plants will look gorgeous in rock gardens, cottage gardens, container gardens, wildlife gardens, meadows, alpine gardens, near ponds, banks, and slopes. Likewise, they are great as ground covers or indoor potted plants.
- Thanks to its lush foliage and attractive blooms, Arabis looks amazing cascading over stone walls and fences.
- Rock Cress plants can make for showy companions to other interesting species of plants. The most common companion plants are Aubrieta, Bellis perennis ‘Pomponette’, Chionodoxa forbesii ‘Blue Giant’, Creeping Phlox, Cushion Spurge, Evergreen Candytuft, Pasque Flower, Sweet Alyssum, and Star of Bethlehem.
- Arabis plants have no toxic effects on humans or animals if they get in contact with them. The leaves and flowers of these plants are actually edible. According to Plants for a Future, the leaves and flowers of Arabis Alpina, for instance, are edible and can be eaten cooked or raw. Both the blooms and the leaves have a nice and subtle cress-like flavour. The same applies to Arabis caucasica, whose leaves can be used as a garnish or as potherbs.
Arabis Features: An Overview
- Arabis species are annual or perennial, herbaceous flowering plants. Depending on the species, the plants can reach from 4 to 31 inches (10-80 cm) in height and up to 18 inches (45 cm) in width.
- The foliage of Rock Cress plants usually consists of simple, entire to lobed, and green to grey-green leaves that emerge on relatively tall, upright, thick, greenish stems. The leaves can measure between 0.4 and 2.4 inches (1-6 cm) in length.
- On some cultivars, such as Arabis caucasica and Arabis ferdinandi-coburgii, the foliage can show up as numerous superb rosettes of greenish to purplish leaves. Most Arabis species have a mat-forming overall growth habit.
- Rock Cress plants bloom throughout the spring months. During this season, they produce a wide diversity of flowers. While most species exhibit small clusters of tiny, fragrant, four-petaled flowers, others bloom with masses of these types.
- The blossoms of Rock Cress plants can appear in various shades of white, cream, pink, lavender, or purple. The blooms of Arabis plants are very delicate and contain nectar.
- Because their lovely flowers contain high amounts of nectar, Arabis plants are highly attractive to various species of pollinators, especially butterflies, bees, and moths. If you are growing them in your garden, expect some visitors from time to time.
- When the flowering season has ended, Rock Cress plants change their blooms with fruits. The fruits are long, slender capsules that contain about 10 to 20 seeds, sometimes even more.
When it comes to lighting conditions, Arabis plants can grow just fine in a wide diversity of conditions. In general, these flowers prefer those locations where they can receive plenty of full sunlight. However, they can also tolerate partial shade to full shade, especially if you live in a region with warm weather.
In terms of temperatures, Rock Cress plants are winter-hardy in the USDA regions 3 to 7. These plants do not behave as other species with delicate flowers. They can usually grow in conditions in which very few can, such as frost, harsh winter temperatures and winds, but also in overall hot and dry weather. The ideal temperatures for Rock Cress plants range from 18-21 °C (65 to 70 °F).
- Arabis Snow Peak is a low-growing perennial that grows best USDA Zones: 4 - 8. It does best in full sun to partial shade areas and is drought tolerant once established.
- Arabis Alpina Snow Peak, also known as Wall Rock Cress, reaches a height of only 6 - 8 inches and is low-maintenance which is perfect for both flower and rock gardens.
- This heirloom groundcover has very fragrant white blooms from mid spring to early summer and will attract bees, while being deer resistant.
- Sow these ground cover seeds at 3 - 4 seeds per plant or approximately 2000 seeds covers 40 square feet. Keep moist until germination.
- Our seeds are always Non-GMO and packaged for the current year.
- Arabis Spring Charm is a low-growing perennial that grows best USDA Zones: 5 - 9. It does best in full sun to partial shade areas and is drought tolerant once established.
- Arabis Biepharophylla Spring Charm, also known as Rock Cress, reaches a height of only 6 inches and is low-maintenance which is perfect for both flower and rock gardens.
- This heirloom groundcover has very fragrant carmine colored blooms from mid spring to early summer and will attract bees.
- Approximately 5000 seeds covers 100 square feet and make sure to keep seeds moist until germination occurs.
- Our seeds are always Non-GMO and packaged for the current year.
- BLOOM TIME: Spring
- HARDINESS ZONE: 3 - 8
- PLANT HEIGHT: 4 - 6
- LIGHT REQUIREMENTS: Sun - Part Shade . . . SOIL / WATER: Dry
- Rockcress grows low and wide making it an excellent ground cover, rock garden plant, or ornamental cascading over walls. It also looks great in pots or hanging baskets. Rockcress can rebloom if it is gently sheared after its first flowering cycle. It is fragrant and attracts bees, butterflies, and birds.
You will not encounter any serious issues with your Rock Cress plants regarding pest infestations. Still, some intruders like aphids, flea beetles, Arabis midge, or cabbage caterpillars may bother your plants occasionally. These pests typically show their presence through tiny eaten spots on the foliage. If you notice this on your plants, try to remove the intruders from them, then apply insecticidal soap or other suitable insecticides until you get rid of the infestation.
Before getting into action, you should know that your Arabis buddies will generally bloom in the second spring after you plant them. And, of course, every year after that. We are telling you this to avoid high expectations or panic in the first year of growth. The best time to plant your Arabis species is in spring or autumn.
As a rule, if you want to plant more Rock Cress specimens in your garden, make sure you plant them at a distance of 5 to 12 inches (12-30 cm) one from another. This process will provide excellent air circulation, also decreasing the chances of fungal diseases showing up.
Soil-wise, Rock Cress plants do well in gritty or sandy substrates that feature very sharp drainage. Although these plants are not picky when it comes to their growing medium, they will benefit more from slightly acidic soils. If your soil is not on the acidic side, you can mulch the soil with a light pine needle to increase acidity and even help it retain moisture.
When you first plant your Arabis beauties, we recommend you fertilize them with a product that is high in nitrogen to boost their growth. After this, you can skip fertilizing them until the plants produce flowers. Once this happens, you can feed your Arabis plants with a fertilizer that is rich in phosphorus once every year whenever their flowering period has ended.
Some Rock Cress species tend to grow very fast and become somewhat leggy with time. If you want to give your plants a fresh, healthy look, you can prune them regularly to keep them in shape and also encourage new growth. Likewise, you can remove any dead flowers you can find during their blooming period to make room for others to show their splendour.
One of the greatest features of Arabis plants is that they become more tolerant of drought once established. However, until then, you will have to water them regularly to help them settle in their new environment. In their first year of growth, it would be wise to water them whenever the top half of the soil has dried out. You can check the soil’s moisture by either poking your finger into the soil or using a moisture meter.
When your Rock Cress plants are mature, you can decrease the frequency of watering. In fact, these are the kind of plants that will not hesitate to give you another chance if you forget about them. We suggest you always check their growing medium in-between waterings to avoid waterlogging and root rot.
Established Rock Cress plants usually need a nice drink only when the soil has dried out completely. But if you allow them to sit in dry soil for longer, no worries! They will still love you once you come back to spoil them anyways.
Have you fallen in love with your Arabis plants and want more specimens around? Well, you can do this at home without spending extra money in a very simple way – propagation. Luckily, Arabis plants can withstand more propagation methods including division or softwood cuttings. Both methods require little effort on your part and typically show spectacular results in a short time.
You can propagate your Rock Cress plants through division only if they are mature and established. In fall, dig the plants out of their growing medium and divide their roots into up to three sections. After this step, all you have to do is replant the divided parts absolutely anywhere you want. That’s all! You can also plant some of them in pots and share your unique experience of growing Rock Cress plants with some of your family members or friends.
If you want to propagate your Rock Cress plants using softwood cuttings, you will have to do it in the summer. Look for young, healthy stems and cut about 4-5 inches (10-13 cm) off them using a sharp knife. Once you have the cuttings, plant them outdoors directly in the soil or indoors in a wide, but short container filled with fresh soil. Place the container in a spot with bright, direct light, and provide the cuttings with water once every five days or so. With proper care, the cuttings will develop some roots in about a month.
With so many Arabis species to check out, you will surely find the perfect one for your collection! Even if many plants that belong to the Arabis family are weeds and not so common in cultivation, there are a few that make great ornamentals, such as Arabis Alpina and Arabis Caucasica. As mentioned before, these plants are so marvellous and low-demanding that it will be pretty hard to resist them! In addition to that, these resilient alpine flowers produce pristine white blooms that will attract beneficial pollinators to your garden which will benefit your other plants as well.
Are you growing Arabis? Let us know in the comments!