Repotting guide

When & how to repot Ceanothus 'Concha' (Ceanothus 'Concha')

Also called Concha California lilac, Concha ceanothus.

More about ceanothus 'concha'

About Ceanothus 'Concha'

Ceanothus 'Concha' · also called Concha California lilac, Concha ceanothus · flowering

Ceanothus 'Concha' is a reliable evergreen California lilac and RHS Award of Garden Merit winner, smothered each late spring in deep cobalt-blue flowers opening from reddish buds, set against small, narrow dark green leaves. Arching and dense, it needs full sun, sharp drainage and minimal watering, attracts pollinators, and is excellent as a border specimen or trained on a warm wall.

Mature size: Roughly 3 m tall and wide, easily kept smaller with light pruning.

Watch for — Root rot from wet soil: Overwatering or poor drainage rots the roots and collapses the plant. Plant in sharply drained soil and avoid summer watering once established.

How to tell ceanothus 'concha' needs repotting

Repotting on a calendar is less reliable than reading the plant. For ceanothus 'concha', 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 ceanothus 'concha') 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 ceanothus 'concha'

Only every 2–4 years, when genuinely crowded. Ceanothus 'Concha' 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, bushy evergreen shrub with arching branches and fine-textured foliage..

What size pot to step ceanothus 'concha' up to

Go up only one pot size — roughly 2–3 cm (about an inch) wider in diameter, no more. Ceanothus 'Concha' 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 ceanothus 'concha' 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 ceanothus 'concha'

Early spring, just as new growth restarts, is the ideal window for ceanothus 'concha'. 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 ceanothus 'concha'

Confirm it actually needs it. Slide ceanothus 'concha' 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 ceanothus 'concha' 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 fertile but free-draining soil, 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 ceanothus 'concha' 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 ceanothus 'concha'

Ceanothus 'Concha' wants fertile but free-draining soil. Needs sharp drainage; tolerates poor and limey ground but may turn chlorotic on shallow chalk. Avoid wet, heavy clay. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting ceanothus 'concha' — frequently asked questions

How often should you repot ceanothus 'concha'?

Only every 2–4 years, when genuinely crowded for ceanothus 'concha'. Only repot ceanothus 'concha' 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 fertile but free-draining soil. The key mistake is over-potting: a too-big pot stays wet and rots the roots.

What size pot does ceanothus 'concha' need?

When is the best time of year to repot ceanothus 'concha'?

Does ceanothus 'concha' like to be root-bound?

Yes — ceanothus 'concha' 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 ceanothus 'concha' after repotting?

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