- Cascading Blue Rock Cress Seeds – Aubrieta Seeds Hybrida Ground Cover Plants
- Rock Cress
- Rock Cress
- Garden Plans For Rock Cress
- Colorful Combinations
- Rock Cress Care Must-Knows
- Plant Rock Cress With:
- Rock Cress for the Rockery…and Elsewhere!
- Growing Rock Cress – How To Grow Rock Cress And Rock Cress Care
- How to Grow Rock Cress
- Care of Rock Cress Plants
Cascading Blue Rock Cress Seeds – Aubrieta Seeds Hybrida Ground Cover Plants
USDA Zones: 4 – 9
Height: 4 inches
Width: 24 inches
Bloom Season: Mid spring to early summer
Bloom Color: Blue
Growth Rate: Moderate
Environment: Full sun to partial shade
Deer Resistant: Yes
Average Germ Time: 14 – 21 days
Light Required: Yes
Depth: Seeds must be covered thinly
Soil Type: Well-drained, pH 6.5 – 7.5
Sowing Rate: Approximately 1000 Aubrieta seeds covers 20 square feet
Moisture: Keep seeds moist until germination
Note: For detailed directions for indoor and outdoor planting, please
Rock Cress Cascading (Aubrieta Hybrida Superbissima Cascade Blue) – If you want a low growing plant to hang out of baskets, hang over a rock wall, or just add to your landscaping color, this Aubrieta cascading Rock Cress is a perfect choice. Rock cress looks beautiful cascading over rock walls and has dark blue blooms in spring.
Sow Aubrieta ground cover seed indoors 6 – 8 weeks before the last expected frost date. Use starter trays using a sterilized mix. Press the Rock Cress ground cover seeds into the soil and thinly cover. The Aubrieta seed needs light to germinate. Transplant into the garden 12 inches apart after frost danger has passed. After frost season has passed, Rock Cress ground cover seeds can be directly sown into a prepared seedbed outdoors.
Shake ‘n Seed – We are now offering shaker bottles filled with our seed starting matrix: rich soil, gardening sand, water absorbing crystals, and starter fertilizer. This not only helps dispense your seed, but it gets it off to a great start! Simply remove lid from shaker bottle, add seed from packet, put back on lid, shake the bottle vigorously for 15 seconds, and then shake your way to beautiful new plants! Use Shake ‘n Seed over good quality soil, and then gently water to keep seed moist until it sprouts. Great for ground covers or mass planting flower seeds.
One of many plants going by the common name of rock cress, this perennial forms splendid mats of color in the spring. As the name implies, this hardy plant is at home in a rock garden and its associated well-drained soil. Rock cress works exceptionally well along walls, borders, and even underneath spring-blooming bulbs to add color to a garden.
Garden Plans For Rock Cress
With its compact, low-growing habit, rock cress acts as a color filler in the lower levels of your garden. For most of the growing season, these plants are a rich green, but during spring they explode into mounds of pastels, ranging from the lightest pinks to the richest purples. The flowers of rock cress are borne so fully that you cannot even see the foliage. The flowers are small but give off a lovely fragrance, so plant some along a path so you can enjoy the fragrance. If this spectacular display of flowers is too short for you, look for varieties with variegated foliage in either white or gold to continue the colorful display. While rock cress are grown most often in the ground, they do well in containers for an eye-catching spring show.
See more of the best plants for rock gardens here.
Rock Cress Care Must-Knows
Knowing that these plants hail from tough mountainous terrain, you can probably guess that their one major requirement is having well-drained soil. The fact that they are often found in some of the smallest cracks and even pure gravel gives you an idea of how sharply drained the soil needs to be for rock cress to thrive. This plant is extremely drought-tolerant and grows well in a container. Due to their rocky upbringings, these plants prefer alkaline soil. Be careful not to overwater or plant in a moist area because too much moisture is sure to kill them.
Rock cress requires full sun. In less than full sun, blossoms will not be as bright or as plentiful. Full sun encourages the tightest habit, too. After their spectacular display of flowers, rock cress benefits from a shearing to stay nice and neat. If you leave spent blossoms on rock cress, there is a good chance it will reseed. Consider this a benefit because rock cress can be fairly short-lived as a perennial. Though they don’t tend to be invasive, you can control where you want more rock cress by sprinkling the seeds.
In areas with warm, humid summers, rock cress may have a shorter life-span. Plant them in part-shade to increase the longevity.
Use these plants for a no-fail trough garden.
Plant Rock Cress With:
Basket-of-gold is one of those plants that loves to grow in the least likely of place — cracks between paving stones, the edge of gravel paths and patios, rocky outcroppings, between the stacked stones of a retaining wall, and more. It loves a baked spot with excellent drainage but will struggle in hot, humid areas and tends not to do well in the South.But where it does well, it’s a showstopper. It will reseed prolifically in little cracks, filling an area each spring with dazzling neon yellows. After it finishes blooming, the grayish-green foliage makes an attractive mat in the perennial garden.
The quintessential cottage flower, pinks are treasured for their grasslike blue-green foliage and abundant starry flowers, which are often spicily fragrant. Depending on the type of pink, flowers appear in spring or summer and tend to be pink, red, white, rose, or lavender, but come in nearly all shades except true blue. Plants range from tiny creeping groundcovers to 30-inch-tall cut flowers, which are a favorite with florists. Foliage is blue-green.Shown above: ‘Firewitch’ dianthus
Sedums are nearly the perfect plants. They look good from the moment they emerge from the soil in spring and continue to look fresh and fabulous all growing season long. Many are attractive even in winter when their foliage dies and is left standing. They’re also drought-tolerant and need very little if any care. They’re favorites of butterflies and useful bees. The tall types are outstanding for cutting and drying. Does it get better than that? Only in the fact that there are many different types of this wonderful plant, from tall types that will top 2 feet to low-growing groundcovers that form mats. All thrive in full sun with good drainage. Ground cover types do a good job of suppressing weeds, but seldom tolerate foot traffic. Some of the smaller ones are best grown in pots or treated as houseplants.
Rock Cress for the Rockery…and Elsewhere!
(Editor’s Note: This article was originally published on December 12, 2009. Your comments are welcome, but please be aware that authors of previously published articles may not be able to promptly respond to new questions or comments.)
Among the most popular rock garden plants are Arabis and Aubrieta, commonly known as rock cress or wall cress. These genera are often considered a beginners plant in the rock garden world but besides rockeries, this group of plants is ideal for growing as a groundcover on slopes, cascading over walls or as an edging plant for borders. Rock cress are considered harbingers of spring as they bloom about the same time as many of the popular spring bulbs. Both genera have evergreen leaves and form trailing mats topped with short racemes. Their flowers are distinct being 4-petaled in the shape of a cross.
The genus Arabis contains about 120 species distributed across the northern hemisphere. Arabis is Latin for Arabia, an area that contains several species of rock cress. In the garden, we only grow a select few species and cultivars. White is the most popular colour but pink to purplish cultivars exists. Aubrieta are very similar to Arabis differing slightly in petal and seedpod shape. This latter genera is named after Claude Aubriet (1668-1743) a French botanical artist. This genus has only 12 species found in Europe and central Asia. While Arabis blooms are most commonly white, Aubrieta come in pink, reddish to purple-blue shades.
The wild form of Arabis alpina growing in northern Newfoundland
Culture is generally quite easy. In the wild they grow in full sun on gravelly, limestone soils often in alpine zones. In the garden, provide them with well-drained soil that is not too acidic. Full sun is best but in hot regions, protection from midday sun is often advantageous. Shear the spent flowers to keep the plants more compact as well as to curb their enthusiasm to self-seed. Older plants can be divided but they germinate easily from seed (do not cover as they need light to germinate) and root easily from herbaceous cuttings. Rock cress are quite hardy, suitable for areas as cold as zone 4, even colder for some species.
Among the Arabis, the most popular species is A. alpina subsp. caucasica. Arabis alpina has a holarctic distribution but the standard species has rather small flowers and wiry stems. The subspecies caucasica has much larger flowers with a more compact habit thus is more desirable as a garden ornamental. There are many cultivars among this subspecies but in North American nurseries ‘Snowcap’ (white) and ‘Spring Charm’ (pink) are perhaps the most popular. Others to look for include ‘Little Treasure Deep Rose’, ‘Pink Sequins’ and ‘Pixie Cream’. Among the Arabis there are several very attractive variegated types. Arabis alpina subsp. caucasica ‘Variegata’ has striking cream-edged foliage. Arabis procurrens ‘Variegata’ has leaf edges widely edged in white. The foliage is much smoother on this species and the flower stems a bit taller than the common rock cress. Considered a synonym of A. procurrens in some books, but as a separate species in others, Arabis ferdinandi-coburgi has several variegated versions; ‘Old Gold’ has yellow-edged foliage, ‘Reversed’ has green leaves with a white center while ‘Variegata’ has white-edged foliage. All of these take on purple tints in winter.
Arabis alpina subsp. caucasica ‘Snowcap’ and ‘Variegata’
Arabis procurrens ‘Variegata’ and ‘Old Gold’
The main Aubrieta grown in gardens is either A. deltoidea and A. X cultorum; the two names are often interchanged. Overall, Aubrieta is smaller in stature than Arabis. There are several named selections including ‘Whitewell Gem’, ‘Novalis Blue’, ‘Purple Gem’, ‘Cascade Red’, ‘Royal Red’ and the ‘Axcent’ series. Like Arabis, Aubrieta also have variegated forms which include ‘Variegata’ with white-edged leaves and ‘Aureovariegata’ whose leaves are yellow edged or even pure yellow. These variegated forms are particularly striking with the purplish blossoms.
Popular cultivars of Aubrieta include ‘Royal Red’, ‘Purple Gem’ and ‘Cascade Red’
Above are A. X cultorum ‘Variegata’ and ‘Aureovariegata’
Growing Rock Cress – How To Grow Rock Cress And Rock Cress Care
Rock cress is an herbaceous perennial and member of the Brassicaceae or mustard family. The flowers and leaves of rock cress are edible. Growing rock cress requires no special skill and this plant is well suited for the novice gardener.
Rock cress has many uses in the garden but its most popular uses are as an attractive border in a rock garden or dangling down over a rock wall or ledge. Rock cresses are alpine plants and will thrive where other plants fail, such as on hills and slopes.
Purple rock cress ground cover (Aubrieta deltoidea) hugs the ground like a mat and displays rich purple flowers in April through the middle of May and has a lovely scent. Rock wall cress (Arabis caucasica) is more likely to bloom in white or pink. Both make attractive low mounds that look great at the edge of retaining wall where they get full sun and excellent drainage.
How to Grow Rock Cress
Rock cress plants are hardy in USDA plant hardiness zones 4-7. They are easily grown from seed and can be directly sown into the garden in early spring or started indoors four to six weeks before the date of your last expected frost.
Rock cress prefers full sun but will tolerate some shade, especially in warmer climates. Space rock cress plants 15 to 18 inches apart and they will fill in quickly forming a mat in any open space.
Care of Rock Cress Plants
Regardless of the type you choose to grow, the care of rock cress plants is relatively minimal. Water new rock cress plants regularly and only when the soil is dry once they are established.
Rock cress ground cover does well in fair soil that has good drainage, and is slightly acidic. Applying a light pine needle mulch helps retain moisture and increase acidity.
A high nitrogen fertilizer can be applied when first planting and a phosphorus fertilizer just after blooming.
Rock cress will bloom the second spring after planting and every year after that. Regular pruning to remove dead flowers will keep the plant healthy and encourage new growth.
It is seldom necessary to treat rock cress for pests or disease.
Now that you know the basics on how to grow rock cress ground cover, you can add an attractive touch to a rock garden or wall.
W. Atlee Burpee & Co.
Aubrieta ‘Hybrids Mix’by George Papadelis
Early flowering bulbs are a sure sign that spring is near. Your bulbs may be planted by themselves, or with some pansies. Perhaps they are interplanted with some early-blooming perennials. Of all the plants we have available for April flowers, Aubrieta is one that combines beautifully with these early season bulbs.
Aubrieta ‘Argenteovariegata’Aubrieta is considered an excellent rock garden plant. Rock gardens can vary, but this term typically describes sunny gardens with smaller, shorter plants that look good growing among rocks. Alpine plants are usually rock garden plants; however, the term “alpines” refers to plants that originate from mountains, above the timberline. They are always compact to better withstand strong winds and are happiest in well-drained “rocky” soil. This is a little confusing, but it is interesting to note that most alpines are rock garden plants, but rock garden plants are not necessarily alpines. Aubrieta is in fact an alpine plant that originated on the mountains of southern Europe and Turkey.
Aubrieta has the common names rock cress and false rock cress. This is an excellent example of when common names can be confusingly tricky. Another popular rock garden plant, Arabis, is also called rock cress. Our focus will remain on Aubrieta, whose characteristics are similar to Arabis.
Aubrieta ‘Dr. Mules’Aubrieta usually begins to bloom in mid to late April and continues into May. They bloom four to six weeks, which is twice as long as the popular creeping phlox. Plants rarely grow taller than 6 inches and may spread as far as 24 inches. Almost all Aubrieta have mat-forming, gray-green leaves that hold their color and remain alive all four seasons. The only maintenance they may require is a light trim of the leaves after flowering is completed.
Their flowers are rarely over 3/4-inch wide, but are produced in masses. Flower colors include white, pink, red, blue, and violet. Many seed grown varieties produce flowers in a range of colors. ‘Royal Blue,’ for example, has flowers of blue, lavender, and violet. ‘Royal Red’ has flowers in shades of red, purple, and magenta. For semi-double flowers, try ‘Bengal,’ which comes in shades of lavender, cerise, and purple. Some varieties are truly one color, such as the dark purple flowers of ‘Whitewell Gem’ and the fluorescent blue flowers of ‘Novalis Blue.’
Aubrieta ‘Red Carpet’Some Aubrieta are grown from cuttings to more perfectly reproduce the desirable characteristics of the parent. Aubrieta ‘Aurea,’ also called golden Aubrieta, has gold-yellow leaves that provide another attractive feature long after its blue-violet flowers have faded. Aubrieta ‘Aurea Variegata’ has bright gold and green bi-colored leaves topped with blue-violet flowers. Aubrieta ‘Argenteovariegata’ forms a extra dense 2- to 4-inch tall mound of creamy white variegated foliage and intense blue flowers. These are all newer varieties that are well worth the effort it may take to find them.
There are several other rock garden or wall plants for sun that bloom about the same time as Aubrieta. Some of the more popular ones include Arabis, candytuft, perennial alyssum, pasque flower, and cushion spurge. All of these are great companions for bulbs that, like rock cress, prefer well-drained, slightly alkaline soil and full sun. The blues, purples, and reds of Aubrieta make perfect companions for pink tulips or golden daffodils.
Aubrieta ‘Whitewell Gem’The garden of Lauren Springer has one combination using Aubrieta that should not go without being mentioned. She planted Aubrieta with the blue-leafed, donkey-tail spurge, Euphorbia myrsinites. Its chartreuse flowers are planted with the purple flowers of rock cress in a dry corner of her yard. She writes “it is perhaps the most psychologically effective combination in the garden, setting the mood for advancing spring, filling me with delight and anticipation each time I go in and out of the otherwise still dormant garden.”
With the winter we have just had, I think it is especially important to celebrate the long-awaited spring. If you can find or create a well-drained sunny site, try using Aubrieta to herald the promise of another gardening season – just like Lauren Springer.
At a glance: Aubrieta deltoidea
Common name: Rock cress, false rock cress
Plant type: Perennial
Plant size: Height: 6 inches, Width: 24 inches
Habit: Mat-forming mound
Hardiness: Zone 4
Flower colors: Purple, blue, violet, red, white and pink
Flower size: 3/4 inch wide
Bloom period: mid-April to May
Leaf color: Gray-green; some varieties are variegated
Light: Full sun
Soil: Well-drained, average fertility
Uses: Rock garden, wall garden, edge of perennial beds
Companion plants: Arabis, candytuft, perennial alyssum, pasque flower, cushion spurge, short tulips and daffodils
Remarks: To prevent legginess, cut back stems after flowering to allow new growth to emerge and maintain compactness.
George Papadelis is the owner of Telly’s Greenhouse in Troy, MI.