Fertilising guide
How to fertilise Sissinghurst White Pulmonaria (Pulmonaria officinalis 'Sissinghurst White')— schedule & NPK
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.
Growth habit: 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.
Watch for — Wilting and leaf scorch: Dry soil or too much sun causes flagging and burnt edges. Water, mulch, and move to cooler, deeper shade if recurring.
What fertiliser sissinghurst white pulmonaria actually wants — and why
Sissinghurst White Pulmonaria is an easy, light foliage feeder — a half-strength balanced liquid feed through the growing months keeps it green without forcing weak, sappy growth.
A balanced general houseplant feed (roughly even N-P-K) is exactly right — it is grown for foliage, so steady, moderate nitrogen for healthy leaves is the goal, not a bloom or root formula.
For the language behind the three numbers on the bottle — what nitrogen, phosphorus and potassium each do — see the NPK ratio explained entry. The short version for sissinghurst white pulmonaria: match the feed to the job the plant is doing right now, not to a generic “plant food” on the shelf.
How often to feed sissinghurst white pulmonaria, and which months
Feeding only earns its keep while the plant is in active growth and can use the nutrients — pour feed into a dormant or low-light plant and it simply builds up as root-burning salt. For sissinghurst white pulmonaria:
Low-maintenance; an annual spring mulch of compost or leaf mould generally covers its needs. A light balanced feed in spring on poorer soils supports vigour. Avoid heavy nitrogen, which softens growth and encourages mildew. Treat that as sparingly through the growing season between spring through early autumn (roughly March to September); ease off in autumn and stop entirely in the low light of winter.
The dormant-season rule matters more than the exact interval: skip feeding entirely when sissinghurst white pulmonaria is resting. For the wider context on indoor feeding rhythms across the seasons, the houseplant fertiliser schedule walks through the year month by month.
What strength to mix for sissinghurst white pulmonaria
Half strength is the safe default for sissinghurst white pulmonaria — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
Feeding always goes onto already-damp soil, never dry roots — water sissinghurst white pulmonaria first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the sissinghurst white pulmonaria watering schedule.
Signs you are over-feeding sissinghurst white pulmonaria
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for sissinghurst white pulmonaria:
- Brown, crispy leaf tips and edges with no sign of underwatering.
- A white, crusty salt deposit on the soil surface or pot rim.
- Weak, pale, stretched new growth that flops.
- Lower leaves yellow and drop while the soil is correctly watered.
Signs you are under-feeding sissinghurst white pulmonaria
- Uniformly pale or yellow-green leaves, oldest first.
- Noticeably small new leaves and stalled growth in good light and season.
- A generally tired, lacklustre look despite correct watering and light.
If the symptoms point at watering, light or roots rather than nutrition, the full sissinghurst white pulmonaria care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of sissinghurst white pulmonaria with plain water until it runs freely from the base every couple of months in the feeding season — it washes out the fertiliser salts that cause brown tips.
Organic vs synthetic feeds for sissinghurst white pulmonaria
Organic options
A diluted seaweed or worm-casting feed, or fish emulsion if you can tolerate the smell indoors. UK: Westland or Baby Bio Organic, dilute seaweed; US: Espoma Indoor! or Neptune's Harvest fish & seaweed. Slow, gentle and hard to overdo.
Synthetic / liquid feeds
A general-purpose houseplant liquid at half strength — UK: Baby Bio, Westland Houseplant Feed or Phostrogen; US: Miracle-Gro Indoor Plant Food or Schultz. Convenient and fast-acting; the only risk is overdoing it.
Brand names are examples, not endorsements, and UK and US ranges differ — check the label’s own NPK and dilution rate, since formulations change.
Fertilising sissinghurst white pulmonaria — frequently asked questions
What fertiliser does sissinghurst white pulmonaria need?
A balanced general houseplant feed (roughly even N-P-K) is exactly right — it is grown for foliage, so steady, moderate nitrogen for healthy leaves is the goal, not a bloom or root formula. Sissinghurst White Pulmonaria is an easy, light foliage feeder — a half-strength balanced liquid feed through the growing months keeps it green without forcing weak, sappy growth.
How often should I feed sissinghurst white pulmonaria?
Low-maintenance; an annual spring mulch of compost or leaf mould generally covers its needs. A light balanced feed in spring on poorer soils supports vigour. Avoid heavy nitrogen, which softens growth and encourages mildew. Low-maintenance; an annual spring mulch of compost or leaf mould generally covers its needs. A light balanced feed in spring on poorer soils supports vigour. Avoid heavy nitrogen, which softens growth and encourages mildew. Treat that as sparingly through the growing season between spring through early autumn (roughly March to September); ease off in autumn and stop entirely in the low light of winter.
What strength of feed for sissinghurst white pulmonaria?
Half strength is the safe default for sissinghurst white pulmonaria — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding sissinghurst white pulmonaria look like?
Brown, crispy leaf tips and edges with no sign of underwatering. A white, crusty salt deposit on the soil surface or pot rim. Weak, pale, stretched new growth that flops. Lower leaves yellow and drop while the soil is correctly watered. Feeding sissinghurst white pulmonaria year-round on a fixed schedule, including dark winter months, is the most common mistake — it cannot use the nutrients in low light and the surplus simply burns the roots and crusts the soil.
Should I flush the soil of sissinghurst white pulmonaria?
Flush the pot of sissinghurst white pulmonaria with plain water until it runs freely from the base every couple of months in the feeding season — it washes out the fertiliser salts that cause brown tips.
Keep reading
- Sissinghurst White Pulmonaria care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water sissinghurst white pulmonaria — the watering schedule
- The houseplant fertiliser schedule — feeding through the year
- NPK ratio explained — what the three numbers on the bottle mean
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- All 3899 fertilising guides in the Growli library