Fertilising guide
How to fertilise Rubrum Epimedium (Epimedium × rubrum)— schedule & NPK
Also called red barrenwort, red epimedium.
More about rubrum epimedium
About Rubrum Epimedium
Epimedium × rubrum · also called red barrenwort, red epimedium · flowering
Epimedium × rubrum is a popular, easy barrenwort grown for both flower and foliage. In spring it bears delicate crimson-and-pale-yellow spurred flowers, while the heart-shaped leaflets emerge tinted red, mature green, and colour brilliant red again in autumn. A reliable, semi-evergreen ground cover for dry shade, it spreads steadily to form weed-suppressing carpets.
Growth habit: Clump-forming, steadily spreading rhizomatous perennial forming a dense ground-cover mat; semi-evergreen, retaining foliage through milder winters.
What fertiliser rubrum epimedium actually wants — and why
Rubrum Epimedium 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 rubrum epimedium: 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 rubrum epimedium, 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 rubrum epimedium:
Top-dress with leaf mould or compost in late winter; a light balanced feed in spring boosts vigour. It tolerates lean soils and rarely needs heavy fertilising once established. 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 rubrum epimedium 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 rubrum epimedium
Half strength is the safe default for rubrum epimedium — 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 rubrum epimedium first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the rubrum epimedium watering schedule.
Signs you are over-feeding rubrum epimedium
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for rubrum epimedium:
- 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 rubrum epimedium
- 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 rubrum epimedium care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of rubrum epimedium 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 rubrum epimedium
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 rubrum epimedium — frequently asked questions
What fertiliser does rubrum epimedium 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. Rubrum Epimedium 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 rubrum epimedium?
Top-dress with leaf mould or compost in late winter; a light balanced feed in spring boosts vigour. It tolerates lean soils and rarely needs heavy fertilising once established. Top-dress with leaf mould or compost in late winter; a light balanced feed in spring boosts vigour. It tolerates lean soils and rarely needs heavy fertilising once established. 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 rubrum epimedium?
Half strength is the safe default for rubrum epimedium — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding rubrum epimedium 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 rubrum epimedium 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 rubrum epimedium?
Flush the pot of rubrum epimedium 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
- Rubrum Epimedium care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water rubrum epimedium — 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