Mature size & growth rate

How big does Lungwort 'Bertram Anderson' (Pulmonaria longifolia) get?

Also called Bertram Anderson Lungwort, Long-Leaved Lungwort, Spotted Dog.

More about lungwort 'bertram anderson'

About Lungwort 'Bertram Anderson'

Pulmonaria longifolia · also called Bertram Anderson Lungwort, Long-Leaved Lungwort · flowering

Lungwort 'Bertram Anderson' is a beautiful shade perennial with narrow, intensely silver-spotted leaves and deep violet-blue flowers in early spring. Neater and more drought-tolerant than some pulmonarias, it excels as ground cover under trees. Moist, humus-rich shade suits it best. Pet-safe according to ASPCA.

Mature size: 30-40 cm tall; 45-60 cm wide

Indoor size vs how big it gets in the wild

Lungwort 'Bertram Anderson' stays fairly low but widens over time — it spreads into a bigger clump by offsets, runners or rhizomes rather than shooting upward. Indoors and in a pot, expect 30-40 cm tall. In the ground with no restriction it is a completely different plant — 45-60 cm wide — which is why the pot, the light and the pruning matter so much for the size you actually end up with.

Size here is about width, not height: the plant builds an ever-wider clump or sends out plantlets and runners while staying relatively short.

Growth rate and years to mature

Lungwort 'Bertram Anderson' is a moderate grower. Realistically, expect three to six years to reach mature indoor size, gaining a steady amount each growing season. Its feeding profile backs this up: apply a light top-dressing of balanced slow-release fertiliser or compost in spring. this species is notably unfussy; over-feeding produces lush but mildew-prone foliage.

Want this turned into the right next pot at the right moment? The pot size calculator and the lungwort 'bertram anderson' repotting guide cover when and how much to size up — pot size is one of the biggest levers on how fast lungwort 'bertram anderson' grows.

How to keep lungwort 'bertram anderson' smaller

You are not stuck with the maximum size. For lungwort 'bertram anderson' specifically, these are the levers, in order of impact:

Divide the clump every year or two — splitting lungwort 'bertram anderson' is the main way to control its spread and refresh it.
Remove runners, plantlets or offsets as they appear if you want it to stay a single tight clump.
Keep it slightly pot-bound; a snug pot naturally limits how wide the clump can get.

The keep-it-smaller method, step by step

Lift the whole plant. Slide lungwort 'bertram anderson' out of its pot in spring when the clump has filled it.
Split the clump. Tease or cut the rootball into two or more sections, each with healthy roots and growth.
Repot one division. Put a single division back in the original pot to reset it to a smaller size; pot or give away the rest.
Remove offsets as they form. Through the year, detach new runners or pups to stop it spreading again.

How to grow lungwort 'bertram anderson' bigger or faster

If you want it to fill the space sooner, push the conditions rather than hoping — for lungwort 'bertram anderson' the accelerators are:

Give it a wider pot and let the clump fill it — width is exactly how this plant gets bigger.
Brighter light speeds up clump and offset production noticeably.
Leave plantlets and offsets attached and feed through the growing season for the fastest spread.

Light is almost always the ceiling. The lungwort 'bertram anderson' light requirements page covers exactly how bright a spot it needs to grow at its potential instead of stalling.

When lungwort 'bertram anderson' outgrows the room (or the pot)

"Too big" usually arrives as one of these signs for lungwort 'bertram anderson':

The clump bulging over the pot rim or splitting the pot — the cue to divide, not to find a bigger room.
A dense centre that goes bare or tired while the edges keep spreading.
Runners or offsets escaping across the shelf or into neighbouring pots.

If it is the pot rather than the room, it is a repotting job, not a goodbye — see the lungwort 'bertram anderson' repotting guide. If you want more of this plant instead of a bigger one, the lungwort 'bertram anderson' propagation guide turns prunings into new plants.

Lungwort 'Bertram Anderson' size — frequently asked questions

How big does lungwort 'bertram anderson' get?

Lungwort 'Bertram Anderson' reaches 30-40 cm tall when grown indoors, and far larger where it grows unrestricted (45-60 cm wide). Size here is about width, not height: the plant builds an ever-wider clump or sends out plantlets and runners while staying relatively short.

Is lungwort 'bertram anderson' slow or fast growing?

Lungwort 'Bertram Anderson' is a moderate grower. Expect three to six years to reach mature indoor size, gaining a steady amount each growing season. Lungwort 'Bertram Anderson' stays fairly low but widens over time — it spreads into a bigger clump by offsets, runners or rhizomes rather than shooting upward.

How long does lungwort 'bertram anderson' take to reach full size?

Roughly three to six years to reach mature indoor size, gaining a steady amount each growing season. Light, pot size and feeding move that timeline more than anything else.

How do I keep lungwort 'bertram anderson' smaller?

Divide the clump every year or two — splitting lungwort 'bertram anderson' is the main way to control its spread and refresh it. Remove runners, plantlets or offsets as they appear if you want it to stay a single tight clump. Keep it slightly pot-bound; a snug pot naturally limits how wide the clump can get.

How can I make lungwort 'bertram anderson' grow bigger or faster?

Give it a wider pot and let the clump fill it — width is exactly how this plant gets bigger. Brighter light speeds up clump and offset production noticeably. Leave plantlets and offsets attached and feed through the growing season for the fastest spread.