Aubrieta

( aw - bree - EH - tuh )

At-A-Glance Information

Aubrieta, frequently misspelled Aubretia, is a genus of flowering herbaceous, evergreen perennial plant species that flower profusely in either full sun or full shade. These multi-purpose garden color boosters are great spilling over retaining walls, as color in potted arrangements, or as an informal groundcover in low-traffic areas of the garden. Flowers range in color from pink to violet to white. Aubrieta is native to southern Europe and central Asia, but has naturalized itself in many areas of Europe and elsewhere due to its tendency to escape the bounds of the garden. Use Aubrieta in mixed beds and borders, as groundcover, or to add color in containers and planters.

Aubrieta Species and Varietals

The genus Aubrieta is a member of the plant family Brassicaceae, and includes about 20 species. The genus was named for French painter Claude Aubriet, who was well-known for painting flowers. The best growing zones for Aubrieta are USDA hardiness zones 4-9 or Sunset growing zones 1-9 and 14-21. To find your zone, click here: Zone Map.

Aubrieta deltoidea (Common Aubrieta, Lilacbush, Purple Rock Cress, Rainbow Rock Cress)
This species is native to the eastern Mediterranean region and Iran. This perennial flowering plant forms a mat ideal for between pavers, in rock gardens, and in breaks in stone walls and retaining walls. It can also be used as a groundcover. Each plant reaches 2-6 inches tall and can spread to 1-1.5 feet.

'Madly Blue Violet'
Produces larger flowers than the species and reblooms in late summer to fall.

'Madly Magenta'
Produces a second bloom in summer or fall, and has large flowers.

'Novalis Blue'
Seed-grown variety with dark blue flowers.

'Rokey's Purple'
Heavy producer of rich purple flowers.

'Argenteovariegata'
With purple blooms and variegated green and white foliage.

'Doctor Mules'
With pink-purple blooms.

'Red Cascade'
With bright carmine-red flowers.

Aubrieta x cultorum
Group of hybrids available in lilac, lavender, and rose. Often in seed mixture.

Aubrieta libanotica (Lebanese Rock Cress)
This species of Aubrieta is native to Lebanon and Syria and is a low-growing, spreading evergreen plant. They can reach up to 2-4 inches tall and have a spread of 8-12 inches at maturity. The species was first described by Swiss botanist Pierre Edmond Boissier. Flowers produced by this hardy species are purple to violet, and these plants can take full sun to partial shade exposure.

Caring for aubrieta

Aubrieta flowers can be purchased as seed and either direct-sown or started indoors, or purchased as starts from a reputable nursery. Space plants between 10 and 12 inches apart for best coverage and airflow. If growing as a groundcover, plant closer to 10 inches apart. Aubrieta should be in full sun exposure; between 6 and 8 hours of direct sun each day is ideal for the best blooms. They will grow in partial shade, but will not flower as profusely and can become a bit leggy if not trimmed back frequently. They prefer lean, rocky soils with a pH of between 6.5 and 7.5. Ensure that soil is well-draining before planting; Aubrieta plants tend to develop issues with fungal diseases if their roots are left in standing water. Apply a thick layer of mulch around the base of plants, ensuring that mulch stays at least a few inches away from the stems. This will increase soil moisture retention, suppress weed growth, and maintain a constant soil temperature.

Water new plantings regularly as they develop a strong root system. Mature plants are considered drought tolerant, and will need supplemental waterings only during periods of drought. Prune these plants after they are done blooming in the middle of summer. Shear or cut plants back by about half to trigger new growth and flowering to begin. Fertilize Aubrieta plants yearly in early springtime using organic compost, pulling back mulch before applying. Work the compost into the soil, water, and then replace mulch around the base of the plant. Aubrieta plants are long-lived perennials in the landscape, able to persist for several years before needing to be replaced.

Growing Aubretia in Containers
Aubretia flowers can do very well in containers. Choose a pot with adequate drainage holes that is about two inches larger in diameter and depth than the root ball or nursery pot. Aubrieta can also be used as a filler around the edges of larger pots. Fill with potting mix amended with perlite or organic matter to improve drainage and nutrient load. Fill in around the outside of the root ball, allowing soil to settle but not packing it down. Apply a layer of mulch on top to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water regularly; Aubretia flowers planted in containers will need more frequent irrigation than those in the ground. As a general rule of thumb, water whenever the top inch of soil feels dry to the touch.

Propagation

The best ways to propagate these plants is via seed or division. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the division method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your Aubrieta plant, follow the instructions below:

Propagating Aubrieta by Seed

Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows.
Harvest your seeds. The seeds of Aubrieta plants are contained inside of the dried flowering heads of plants, which will turn brown and dry when mature. Once they have dried out completely, cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will begin to release the seeds, and this process can be helped along with some rough handing (shaking of the bag). Once seeds have been released, take them out of the bag and put them in a container so you can work with them.
Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes about 28 days from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.

Propagating Aubrieta by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil (any kind will do, though it does need to be well-draining), compost, and pots (12 inch pots will do, and these are only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in spring; to propagate by division, follow these steps:

Gather your materials. Using a shovel, dig up your existing plant. Start from the outside and work your way in to avoid damaging the roots. Once you have worked it up out of the ground, lay it out.
Start to tease apart the roots with your gloved fingers. Once the roots are untangled, separate your plant into segments, ensuring that each one has at least one thick root section.
Prepare your pot(s) or new planting site(s) with amended, well-draining soil. You can either bring in new soil or simply amend your existing soil with compost to complete this task. Then, plant your divisions and water them in.
Apply a thick layer of mulch around the new planting to protect it from cold weather as it acclimates to its new home. Then, enjoy watching it sprout over the spring and summer seasons.