Repotting guide

When & how to repot White Campion (Silene latifolia)

Also called White Campion, White Cockle, Evening Lychnis.

More about white campion

About White Campion

Silene latifolia · also called White Campion, White Cockle · flowering

Silene latifolia is a dioecious biennial or short-lived perennial native to disturbed ground, roadsides, and arable margins across Europe and introduced across North America. Its white, five-petalled flowers open in the evening and are fragrant, attracting moths and other nocturnal pollinators. The most critical care note is that it resents waterlogging, especially in winter, and needs sharp drainage to persist. As with other Silene species it contains saponins and is treated as mildly toxic to pets in the absence of ASPCA listing.

Mature size: 60–100 cm tall and 30–60 cm wide.

How to tell white campion needs repotting

Repotting on a calendar is less reliable than reading the plant. For white campion, 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 white campion) 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 white campion

Only every 2–4 years, when genuinely crowded. White Campion 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. Upright, biennial or short-lived perennial with sticky, hairy stems and opposite elliptic leaves; separate male and female plants needed for seed set..

What size pot to step white campion up to

Go up only one pot size — roughly 2–3 cm (about an inch) wider in diameter, no more. White Campion 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 white campion 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 white campion

Early spring, just as new growth restarts, is the ideal window for white campion. 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 white campion

Confirm it actually needs it. Slide white campion 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 white campion 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 well-drained, neutral to alkaline, 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 white campion 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 white campion

White Campion wants well-drained, neutral to alkaline. Thrives in chalk or sandy soils with a neutral to alkaline pH; amend heavy clay with grit to improve drainage, and avoid rich compost. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting white campion — frequently asked questions

How often should you repot white campion?

Only every 2–4 years, when genuinely crowded for white campion. Only repot white campion 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 well-drained, neutral to alkaline. The key mistake is over-potting: a too-big pot stays wet and rots the roots.

What size pot does white campion need?

When is the best time of year to repot white campion?

Does white campion like to be root-bound?

Yes — white campion 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 white campion after repotting?

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