Repotting guide

When & how to repot Cushion Draba (Draba bruniifolia)

Also called Cushion Draba, Brunii-leaved Whitlow Grass.

More about cushion draba

About Cushion Draba

Draba bruniifolia · also called Cushion Draba, Brunii-leaved Whitlow Grass · flowering

Cushion Draba is a tight-mounding alpine perennial from the Caucasus and Turkey, forming dense evergreen cushions of minute hairy rosettes studded with bright yellow flowers in early to mid-spring. A classic rock garden and alpine trough plant, it is fully frost-hardy and thrives in open scree conditions with perfect drainage and full sun.

Mature size: 3–8 cm tall, spreading 10–20 cm wide

Watch for — Vine weevil grubs: Larvae can attack roots in container-grown plants, causing sudden collapse. Check roots when repotting and apply biological nematode controls (Steinernema kraussei) in late summer or early autumn.

How to tell cushion draba needs repotting

Repotting on a calendar is less reliable than reading the plant. For cushion draba, watch for these signs:

Roots spiralling thickly out of the drainage holes or pushing the whole plant up out of the pot.
The pot is so packed that water runs straight through in seconds and barely wets the soil.
It has split a plastic pot, or the rootball is a solid mass with almost no soil left when you slide it out.
Growth and (for cushion draba) flowering have clearly stalled despite good light and feeding — but remember this plant likes being snug, so a little crowding alone is not a reason to repot.

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 cushion draba

Only every 2–4 years, when genuinely crowded. Cushion Draba is one of the plants that genuinely prefers a snug pot — it grows and flowers better with its roots a little restricted, so resist the urge to repot it on schedule. Dense, cushion-forming evergreen perennial with tightly packed rosettes.

What size pot to step cushion draba up to

Go up only one pot size — roughly 2–3 cm (about an inch) wider in diameter, no more. Cushion Draba positively prefers a snug pot: it flowers and grows better when the roots are a little restricted. The single biggest repotting mistake here is over-potting — dropping cushion draba into a pot two or three sizes up. All that surplus soil holds water the small root system cannot use, stays cold and wet, and rots the roots within weeks. When in doubt, choose the smaller pot.

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 cushion draba

Early spring, just as new growth restarts, is the ideal window for cushion draba. The plant is moving into its strongest growth phase and re-roots into fresh soil quickly. Avoid repotting in winter dormancy or, for flowering plants, while it is in bud or bloom — recovery is slowest then and you risk dropping the flowers.

Step-by-step: repotting cushion draba

Confirm it actually needs it. Slide cushion draba out and check the roots. Only continue if it is genuinely packed — this plant prefers a snug pot, so if there is still soil and room, put it straight back.
Pick a pot only one size up. Choose a pot just 2–3 cm wider with good drainage. Resist anything bigger; over-potting is the main killer here.
Ease it out gently. Water lightly the day before, then tip cushion draba out, supporting the base. Tease the outer roots free only enough to stop them circling.
Repot at the same depth. Add a layer of fresh very sharply draining alpine scree mix, set the plant so the soil line sits exactly where it did before, and backfill around the sides, firming lightly.
Settle it in. Water once to settle the soil, then let it sit. Hold off on more water until the top of the soil dries — fresh soil around a small root system stays wet for a while.

Aftercare

Because the new soil holds more water than the old crammed rootball did, ease right back on watering — let the top of the soil dry before you water cushion draba again, or you will rot the roots in the very pot you just moved it to. Keep it out of harsh direct sun for a fortnight. Do not fertilise for about 4 weeks — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for cushion draba

Cushion Draba wants very sharply draining alpine scree mix. Best in a 60:40 mix of coarse horticultural grit to loam-based compost, or pure scree composed of limestone or granite chippings with minimal organic matter. Neutral to slightly alkaline pH (6.5–7.5). Avoid rich, moisture-retentive composts entirely. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting cushion draba — frequently asked questions

How often should you repot cushion draba?

Only every 2–4 years, when genuinely crowded for cushion draba. Only repot cushion draba every 2–4 years, and only when it is genuinely root-bound — it flowers and grows best slightly crowded. Step up just one pot size in spring using very sharply draining alpine scree mix. The key mistake is over-potting: a too-big pot stays wet and rots the roots.

What size pot does cushion draba need?

When is the best time of year to repot cushion draba?

Does cushion draba like to be root-bound?

Yes — cushion draba genuinely flowers and grows best when slightly pot-bound, so do not rush to repot it. The mistake to avoid is over-potting into a much larger pot: the excess soil stays wet, the roots cannot use it, and the plant rots. Only repot every few years and only one snug size up.

Should you fertilise cushion draba after repotting?

Not immediately. Wait about 4 weeks after repotting cushion draba. Fresh mix already contains nutrients, and feeding freshly cut or disturbed roots burns them. Resume your normal feeding routine once you see new growth.