Repotting guide

When & how to repot Alpine Rock Cress (Arabis alpina)

Also called Alpine Rock Cress, Mountain Rock Cress.

More about alpine rock cress

About Alpine Rock Cress

Arabis alpina · also called Alpine Rock Cress, Mountain Rock Cress · flowering

A vigorous, mat-forming perennial bearing fragrant white flowers in spring. Native to alpine and subalpine rocky habitats across Europe and Asia, it thrives in well-drained, gritty soils with full sun. Popular in rock gardens, dry walls, and as a ground cover on slopes. Trim after flowering to prevent sprawling and self-seeding.

Mature size: 15–25 cm tall, 45–60 cm wide

Watch for — Self-seeding and invasiveness: Arabis alpina can self-seed prolifically, potentially spreading beyond its intended area. Deadhead or trim spent flowers promptly after bloom to limit unwanted spread in the garden.

How to tell alpine rock cress needs repotting

Repotting on a calendar is less reliable than reading the plant. For alpine rock cress, watch for these signs:

Roots growing out of the drainage holes, or the rootball lifting the plant proud of the rim.
Soil that has shrunk away from the pot sides and no longer holds water.
The pot is unstable because the plant has grown top-heavy.
Old, compacted, broken-down mix that stays wet too long — for a succulent that is a rot risk, so refresh it even if the pot size is fine.

For the underlying biology of a pot-bound root system and why it stalls a plant, see our guide to spotting and fixing a root-bound plant.

How often to repot alpine rock cress

Every 2–3 years, into bone-dry mix. Alpine Rock Cress's growth habit — spreading, mat-forming semi-evergreen perennial — sets the pace. A vigorous, mat-forming perennial bearing fragrant white flowers in spring. Native to alpine and subalpine rocky habitats across Europe and Asia, it thrives in well-drained, gritty soils with full sun. Popular in rock gardens, dry walls, and as a ground cover on slopes. Trim after flowering to prevent sprawling and self-seeding.

What size pot to step alpine rock cress up to

Use a pot only one size up — or even the same pot with fresh gritty mix if the roots have room. Alpine Rock Cress stores water and rots in a large pot of slow-drying soil. A tight terracotta pot that dries fast is far safer than a generous plastic one. Never up-pot a succulent by several sizes.

Not sure of the exact diameter? Our pot size calculator takes the current pot and root spread and tells you the right next size — it deliberately recommends a single step up, never a big jump.

The best time of year to repot alpine rock cress

Spring or summer, while alpine rock cress is in active growth and warm, is best — roots recover fastest then, and the plant is not sitting in cool damp soil. Avoid repotting a succulent in winter dormancy.

Step-by-step: repotting alpine rock cress

Repot dry. Do not water alpine rock cress for several days first. Working with dry roots and dry mix dramatically lowers the rot risk for a succulent.
Pick a snug, fast-draining pot. Choose terracotta one size up at most, with a drainage hole. Have gritty well-drained, moderately fertile, neutral to slightly alkaline soil ready.
Tip it out and clean the roots. Slide the plant out, crumble off the old soil, and trim any black, mushy or dead roots with clean snips.
Pot into dry mix. Set alpine rock cress at its original depth in dry gritty mix, firming gently. Do not bury the stem deeper than it was.
Wait a week before watering. Leave it completely dry and out of harsh sun for about 7 days so any damaged roots callus. Only then water lightly.

Aftercare

Keep alpine rock cress completely dry and out of fierce sun for about a week so any nicked roots callus before they meet moisture; watering a freshly repotted succulent is the classic way to rot it. Then resume the normal lean, dry rhythm. Do not fertilise for about 3 weeks — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for alpine rock cress

Alpine Rock Cress wants well-drained, moderately fertile, neutral to slightly alkaline soil. Sandy or gritty loam is ideal. Tolerates poor, rocky soils. Amend clay soils generously with horticultural grit. pH 6.0–7.5. Good drainage prevents root rot, particularly in winter. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting alpine rock cress — frequently asked questions

How often should you repot alpine rock cress?

Every 2–3 years, into bone-dry mix for alpine rock cress. Repot alpine rock cress every 2–3 years into a snug pot of well-drained, moderately fertile, neutral to slightly alkaline soil, ideally in spring or summer. Let it sit in dry soil and do not water for about a week afterwards so any nicked roots can callus. Over-potting and watering straight away is what rots succulents.

What size pot does alpine rock cress need?

When is the best time of year to repot alpine rock cress?

Should you water alpine rock cress after repotting?

No — not straight away. Repot alpine rock cress into dry mix and wait about a week before the first watering so any damaged roots callus over. Watering a freshly repotted succulent is the single most common way to rot one.

Should you fertilise alpine rock cress after repotting?

Not immediately. Wait about 3 weeks after repotting alpine rock cress. Fresh mix already contains nutrients, and feeding freshly cut or disturbed roots burns them. Resume your normal feeding routine once you see new growth.