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Rock Cress
Aubrieta
Also comes in blue, red, pink and white.
Rock Cress blooms from April through May.
Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.
Growing Rock Cress
Plant it in full sun. It prefers low water. It is hardy in USDA zones 4–8. Expect it to reach about 4 in tall and 16 in wide at maturity, in roughly 2 years (checked).
No toxicity note is on file for Rock Cress. That is not a clearance: check its safety for people and pets before planting.
What was checked
Mature height and spread, hardiness zones, sun, water, bloom months and color and the trait tags were checked against named botanical sources for this plant, with what the sources could not settle written down; years to mature size rests on a recorded house rule where no publisher states one, and is marked so; its common name and alternate names have not been checked yet. Each fact above carries its own mark. The planting, spacing and size sections are derived from these checked facts by a fixed rule, not checked separately, and the plant type is the library's own classification.
When to plant Rock Cress
Plant Rock Cress in early spring as soon as the soil is workable, or in early fall at least six weeks before your first frost, so roots establish in cool weather. In zone 6, the middle of its hardy zones 4 to 8, spring means March to May and fall means August or September. Once settled, it blooms from April to May.
Month-by-month timing for your zone is on the planting calendar; if you garden near zone 6, the middle of this plant's hardy range, start with zone 6 in March. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.
How big does Rock Cress get?
4 intall5 ft 7 inan adult16 inwideSee Rock Cress in a garden plan: the planner shows it in 3D beside everything else you add, growing toward this size over the years.
How far apart to plant Rock Cress
Derived from the mature spread above by a fixed rule, not checked separately: spacing is the spread, center to center.
Space Rock Cress about 16 in apart, center to center, so each plant has room to reach its full width.
Add Rock Cress to a garden plan and the planner draws it at its full width, so you see the spacing before you buy.
Where these facts come from
Rock Cress' height, spread, hardiness zones, sun, water, bloom months and color, years to mature size, trait tags, soil, diseases, pests and toxicity were checked against 8 published sources on August 16, 2026. Each one is linked below with every fact it carried, which can include a fact this page still marks as not yet checked, because a source carrying a value is not the same as the value being held to the standard. Facts not in that list, and the planting, spacing and size sections, are not covered by these sources.
- RHSRoyal Horticultural Societyheight, spread, sun, water, bloom months and color, years to mature size, soil, diseases and pests
- Cornell Cooperative ExtensionCornell University, Home Gardening Flower Growing Guidesheight, spread, hardiness zones, sun, water, bloom months and color, soil and diseases
- michigangardener.comMichigan Gardener magazine (Plant Focus by George Papadelis, Telly's G...height, spread, hardiness zones, sun, bloom months and color, trait tags and soil
- High Country Gardenssun, water, bloom months and color, trait tags and soil
- High Country Gardensheight, spread, hardiness zones, water and pests
- BBC Gardeners' WorldMagazineheight, spread, soil and toxicity
- RHSRoyal Horticultural Societybloom months and color and trait tags
- Penn State Extensionhardiness zones
How the checking works, and what each standard covers, is on the verified plants page.
Good to know about Rock Cress
Curated from university extensions, botanic gardens and other primary sources, with the source named on every note. A note reports what its source says; where that differs from a fact above, the fact above is this entry's stored value, and its mark says whether it has been checked.
Worth knowing
Rock cress names two different plants: Aubrieta, the purple or false rock cress, and Arabis, the true rock cress, usually white or pink. Check flower color and the label. per Wisconsin and Colorado State
Cool and moist, or dry?
The sources seem to clash: one calls it cool and moist, others drought resistant. The real rule is sharp drainage. Give gritty soil that never stays wet. per Wisconsin and RHS
Shear hard after bloom
Shear the whole mat back by about half right after the spring bloom. It keeps the mat dense and stops the center going bare and leggy. per Colorado State and RHS
Deer resistant
Listed among plants deer do not favor, and reported deer resistant. As with any such plant, very hungry deer may still sample it. per Wisconsin
Early nectar for pollinators
It blooms so early that it feeds bees and butterflies when little else is open. RHS marks it as beneficial for pollinators. per Minnesota and RHS
Short-lived in hot summers
It prefers cool conditions and struggles in hot, humid summers, where it tends to be short-lived. This, more than winter cold, sets its southern limit. per Wisconsin and RHS
What pairs well with Rock Cress
Good companions share its growing conditions and add something it lacks: an earlier or later bloom, a lower carpet in front, or structure through winter.
Mullein
Shares full sun and low water; blooms in early summer as this one finishes; stands well above at 4 ft, a canopy to plant beneath; both offer pollinator forage, in different months.
Cosmos
Shares full sun and low water; blooms in early summer as this one finishes; stands well above at 3.5 ft, a canopy to plant beneath; both offer pollinator forage, in different months.
Russian Sage
Shares full sun and low water; blooms in midsummer, extending the bed's season; stands well above at 4 ft, a canopy to plant beneath; both offer pollinator forage, in different months.
Delphinium
Shares full sun and low to moderate water; blooms in early summer as this one finishes; stands well above at 4.5 ft, a canopy to plant beneath; both offer pollinator forage, in different months.
Potentilla
Shares full sun and low water; blooms in early summer as this one finishes; both offer pollinator forage, in different months; taller at 3 ft, for the layer behind it.
Beautyberry
Takes full sun to part sun and low to moderate water; blooms in early summer as this one finishes; stands well above at 5 ft, a canopy to plant beneath; both offer pollinator forage, in different months.
Cleome
Shares full sun and low to moderate water; blooms in early summer as this one finishes; stands well above at 4 ft, a canopy to plant beneath; both offer pollinator forage, in different months.
Oregano
Shares full sun and low water; blooms in early summer as this one finishes; both offer pollinator forage, in different months; taller at 1.5 ft, for the layer behind it.
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Drop this plant onto a 3D plan, see how it fills in, and watch your whole garden bloom across the year.