Repotting guide

When & how to repot Sissinghurst White Pulmonaria (Pulmonaria officinalis 'Sissinghurst White')

Also called Sissinghurst White lungwort, white lungwort.

More about sissinghurst white pulmonaria

About Sissinghurst White Pulmonaria

Pulmonaria officinalis 'Sissinghurst White' · also called Sissinghurst White lungwort, white lungwort · flowering

'Sissinghurst White' is a classic lungwort with large, pure white spring flowers above broad, silver-spotted green leaves. It brightens shady borders and woodland gardens and offers early nectar for bees. As with the genus, it isn't individually ASPCA-listed, so treat it cautiously around cats and dogs.

Mature size: 25-30 cm (10-12 in) tall, spreading 30-45 cm (12-18 in) wide.

How to tell sissinghurst white pulmonaria needs repotting

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

Only every 2–4 years, when genuinely crowded. Sissinghurst White Pulmonaria 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. Low, clump-forming, semi-evergreen perennial spreading steadily by rhizomes into weed-suppressing ground cover. White flowers open early in spring on short stems before the main flush of bristly, spotted leaves..

What size pot to step sissinghurst white pulmonaria up to

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

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

Confirm it actually needs it. Slide sissinghurst white pulmonaria 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 sissinghurst white pulmonaria 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 moist, humus-rich, well-drained loam, 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 sissinghurst white pulmonaria 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 sissinghurst white pulmonaria

Sissinghurst White Pulmonaria wants moist, humus-rich, well-drained loam. Wants fertile woodland soil rich in organic matter that holds moisture without sitting wet. Neutral to slightly alkaline pH suits it. Add leaf mould or compost; avoid hot, dry spots. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting sissinghurst white pulmonaria — frequently asked questions

How often should you repot sissinghurst white pulmonaria?

Only every 2–4 years, when genuinely crowded for sissinghurst white pulmonaria. Only repot sissinghurst white pulmonaria 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 moist, humus-rich, well-drained loam. The key mistake is over-potting: a too-big pot stays wet and rots the roots.

What size pot does sissinghurst white pulmonaria need?

When is the best time of year to repot sissinghurst white pulmonaria?

Does sissinghurst white pulmonaria like to be root-bound?

Yes — sissinghurst white pulmonaria 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 sissinghurst white pulmonaria after repotting?

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