Repotting guide

When & how to repot Trevi Fountain Pulmonaria (Pulmonaria 'Trevi Fountain')

Also called Trevi Fountain lungwort, blue lungwort.

More about trevi fountain pulmonaria

About Trevi Fountain Pulmonaria

Pulmonaria 'Trevi Fountain' · also called Trevi Fountain lungwort, blue lungwort · flowering

'Trevi Fountain' is a lungwort grown for unusually pure cobalt-blue spring flowers held above silver-spotted green leaves. It forms neat clumps for moist, shaded borders and woodland gardens and is loved by early bees. Pulmonaria isn't individually ASPCA-listed, so treat it cautiously around cats and dogs.

Mature size: 25-30 cm (10-12 in) tall, spreading 45-60 cm (18-24 in) wide.

Watch for — Wilting and scorch: Dry roots or too much sun cause flagging and burnt leaf edges. Water, mulch, and move to deeper, cooler shade if recurring.

How to tell trevi fountain pulmonaria needs repotting

Repotting on a calendar is less reliable than reading the plant. For trevi fountain 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 trevi fountain 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 trevi fountain pulmonaria

Only every 2–4 years, when genuinely crowded. Trevi Fountain 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 slowly by rhizomes into tidy ground cover. Blue flower clusters open early in spring on short stems above the bristly, silver-marked leaves..

What size pot to step trevi fountain pulmonaria up to

Go up only one pot size — roughly 2–3 cm (about an inch) wider in diameter, no more. Trevi Fountain 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 trevi fountain 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 trevi fountain pulmonaria

Early spring, just as new growth restarts, is the ideal window for trevi fountain 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 trevi fountain pulmonaria

Confirm it actually needs it. Slide trevi fountain 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 trevi fountain 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 trevi fountain 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 trevi fountain pulmonaria

Trevi Fountain Pulmonaria wants moist, humus-rich, well-drained loam. Wants fertile woodland soil rich in organic matter that stays moist but not waterlogged. Neutral to slightly alkaline pH is fine. Add leaf mould or compost; avoid hot, dry, free-draining sites. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting trevi fountain pulmonaria — frequently asked questions

How often should you repot trevi fountain pulmonaria?

Only every 2–4 years, when genuinely crowded for trevi fountain pulmonaria. Only repot trevi fountain 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 trevi fountain pulmonaria need?

When is the best time of year to repot trevi fountain pulmonaria?

Does trevi fountain pulmonaria like to be root-bound?

Yes — trevi fountain 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 trevi fountain pulmonaria after repotting?

Not immediately. Wait about 4 weeks after repotting trevi fountain 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.