The rich purple of Rock Cress with its tiny four-petaled flowers bloom in such a tight mass of dazzling color any spring garden would lack luster without this stunning perennial. Often known by its common name, Aubrieta, this lovely spring perennial should be on your “must have” list. Gardeners in the Rocky Mountains (with the exception of Utah where it is very popular) have not taken to Rock Cress yet, despite its high status of being in the tough, hardy Alpine family. Aubrietia’s origins are the Mediterranean regions. These regions have similar soil and climate challenges as western gardens. This powerful perennial prefers a sunny location in a cooler climate and is a snap to grow.
Purple Rock Cress has many uses. The first is the “hot” look its color adds to the garden. Aubrieta spreads forming a mass of rich, deep purple flowers to contrast with the many yellow flowers and red tulips of spring.
Another talent of Aubrietia’s is the way it grows, which depends on where it is planted. Purple Rock Cress can hug the ground like a mat. Its lovely foliage of a silvery gray-green has a tendency appear attractive all season and often performs as an evergreen. Aubretia’s spoon or oval-shaped leaves form a tight mass that spreads slowly. In April when the flowers open, Aubrieta creates gorgeous rich purple carpeting that will bloom for about six weeks into mid-May.
Rock Cress in your Alpine Garden
Aubrieta is an Alpine rock garden perennial that thrives in difficult planting areas. It can be planted on steep slopes where it will fill in and hold the soil, or can cascade gracefully over rock walls. A retaining wall with its good drainage may be a trial to many plants but Aubrieta thrives in this environment. It maintains its excellent tight mat appearance even when dangling over a rock wall.
Rock Cress is hardy to a zone-four or minus thirty degrees and requires no special skill to grow, making it a good plant for a novice gardener to start with. Good drainage is a must and regular fertilizing at the same time lawns are fed in the spring is adequate. Aubrieta will not bloom without a cold winter treatment called vernalization. It is completely pest and disease free. Prune the spent flowers when it finishes blooming to keep the plant healthy and encourage new growth.
Side note: Confused about the correct spelling for aubretia/aubrieta/aubrietia?
According to gardener Ken Thompson, aubrieta is one of the most commonly misspelled flower names (just behind ginkgo and fuchsia). According to Thompson, “the problem here is that the genus is named after French flower painter Claude Aubriet, but the correct generic name aubrieta has never tripped off the tongue for English speakers. So the i has tended to migrate, giving us the common English name of aubretia. Or sometimes an extra i has appeared, giving us aubrietia.”
I’ve spelled the word various ways in this article, just in case someone out there is Googling for a different spelling, but if you want to be “in the know,” the correct spelling is aubrieta. Different versions of the pronunciation also abound on the Internet, but according to the Oxford English Dictionary website, the word is pronounced, o-BREE-shuh.