Fertilising guide
How to fertilise White Arrow Arum (Peltandra sagittifolia)— schedule & NPK
Also called White Arrow Arum, Spoonflower, White Arrow-arum.
More about white arrow arum
About White Arrow Arum
Peltandra sagittifolia · also called White Arrow Arum, Spoonflower · flowering
A native southeastern US wetland perennial prized for its snowy-white, scoop-shaped spathe and glossy arrow-shaped leaves. It thrives in boggy margins, shallow ponds, and rain gardens. Plant in consistently wet or waterlogged soil in full sun to partial shade; tolerates standing water. Minimal fertiliser needed in rich organic soils. Spreads slowly by offsets.
Growth habit: Clump-forming aquatic perennial emerging from stout rhizomes; deciduous in cold winters
What fertiliser white arrow arum actually wants — and why
White Arrow Arum 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 white arrow arum: 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 white arrow arum, 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 white arrow arum:
Generally unnecessary in nutrient-rich bog or pond soil. If grown in containers, apply a balanced aquatic or slow-release fertiliser once in spring at half the recommended rate. 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 white arrow arum 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 white arrow arum
Half strength is the safe default for white arrow arum — 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 white arrow arum first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the white arrow arum watering schedule.
Signs you are over-feeding white arrow arum
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for white arrow arum:
- 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 white arrow arum
- 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 white arrow arum care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of white arrow arum 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 white arrow arum
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 white arrow arum — frequently asked questions
What fertiliser does white arrow arum 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. White Arrow Arum 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 white arrow arum?
Generally unnecessary in nutrient-rich bog or pond soil. If grown in containers, apply a balanced aquatic or slow-release fertiliser once in spring at half the recommended rate. Generally unnecessary in nutrient-rich bog or pond soil. If grown in containers, apply a balanced aquatic or slow-release fertiliser once in spring at half the recommended rate. 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 white arrow arum?
Half strength is the safe default for white arrow arum — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding white arrow arum 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 white arrow arum 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 white arrow arum?
Flush the pot of white arrow arum 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
- White Arrow Arum care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water white arrow arum — the watering schedule
- The houseplant fertiliser schedule — feeding through the year
- NPK ratio explained — what the three numbers on the bottle mean
- How to fertilise disocactus phyllanthoides
- How to fertilise selenicereus pteranthus
- How to fertilise euphorbia milii 'lutea'
- All 8452 fertilising guides in the Growli library