Fertilising guide
How to fertilise Palmarosa (Cymbopogon martinii)— schedule & NPK
Also called Rosha Grass, Turkish Geranium Grass, Indian Geranium.
More about palmarosa
About Palmarosa
Cymbopogon martinii · also called Rosha Grass, Turkish Geranium Grass · herb
Palmarosa is a tall tropical grass prized for its geraniol-rich, rose-scented leaves, widely used in perfumery and aromatherapy. It grows in large, arching clumps and thrives in full sun with good drainage. Not listed as toxic to pets by the ASPCA.
Growth habit: Clump-forming tropical perennial grass
What fertiliser palmarosa actually wants — and why
Palmarosa is a soft, fast leafy herb that you harvest hard — a modest balanced feed keeps tender growth coming without tipping it into bland or bolting.
A balanced general feed (even N-P-K) at modest strength — enough nitrogen to keep replacing the leaves you pick, but not so much that flavour thins or it bolts to seed.
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 palmarosa: 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 palmarosa, 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 palmarosa:
Apply a balanced slow-release fertiliser (e.g. 10-10-10) at the start of the growing season. A light liquid feed monthly through summer supports leaf oil production without excessive leafy growth. In practice: a balanced liquid feed every few weeks through the main growing and harvesting season (spring through early autumn), more often the harder you are picking it.
The dormant-season rule matters more than the exact interval: skip feeding entirely when palmarosa 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 palmarosa
Half strength is a sensible default for palmarosa — enough to fuel regrowth after cutting, gentle enough that the leaves stay aromatic rather than watery.
Feeding always goes onto already-damp soil, never dry roots — water palmarosa first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the palmarosa watering schedule.
Signs you are over-feeding palmarosa
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for palmarosa:
- Fast, soft, pale growth with diluted, less aromatic flavour.
- Early bolting (running to flower) and a bitter edge.
- Salt crust and scorched tips on container plants.
Signs you are under-feeding palmarosa
- Pale, slow regrowth after cutting and small leaves.
- A tired, stalled plant that cannot keep up with harvesting.
- Yellowing older leaves in a long-spent pot.
If the symptoms point at watering, light or roots rather than nutrition, the full palmarosa care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Pot-grown palmarosa builds up feed salts quickly — water until it drains each time and flush the pot with plain water every few weeks, especially on a sunny windowsill.
Organic vs synthetic feeds for palmarosa
Organic options
A diluted seaweed feed or worm-casting tea keeps soft growth coming without overdoing it. UK: dilute seaweed or Westland; US: Espoma Garden-tone or Neptune's Harvest. Gentle, hard to overdo, flavour-friendly.
Synthetic / liquid feeds
A balanced liquid feed at half strength through harvesting — UK: Phostrogen, Baby Bio or Westland; US: Miracle-Gro all-purpose at half strength. Fast regrowth; just do not overdo the nitrogen.
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 palmarosa — frequently asked questions
What fertiliser does palmarosa need?
A balanced general feed (even N-P-K) at modest strength — enough nitrogen to keep replacing the leaves you pick, but not so much that flavour thins or it bolts to seed. Palmarosa is a soft, fast leafy herb that you harvest hard — a modest balanced feed keeps tender growth coming without tipping it into bland or bolting.
How often should I feed palmarosa?
Apply a balanced slow-release fertiliser (e.g. 10-10-10) at the start of the growing season. A light liquid feed monthly through summer supports leaf oil production without excessive leafy growth. Apply a balanced slow-release fertiliser (e.g. 10-10-10) at the start of the growing season. A light liquid feed monthly through summer supports leaf oil production without excessive leafy growth. In practice: a balanced liquid feed every few weeks through the main growing and harvesting season (spring through early autumn), more often the harder you are picking it.
What strength of feed for palmarosa?
Half strength is a sensible default for palmarosa — enough to fuel regrowth after cutting, gentle enough that the leaves stay aromatic rather than watery.
What does over-feeding palmarosa look like?
Fast, soft, pale growth with diluted, less aromatic flavour. Early bolting (running to flower) and a bitter edge. Salt crust and scorched tips on container plants. Over-feeding palmarosa with strong nitrogen is the usual mistake — it grows fast and lush but the leaves turn bland and it bolts to flower sooner, ending the useful harvest early.
Should I flush the soil of palmarosa?
Pot-grown palmarosa builds up feed salts quickly — water until it drains each time and flush the pot with plain water every few weeks, especially on a sunny windowsill.
Keep reading
- Palmarosa care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water palmarosa — 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 pelargonium 'lemon fancy'
- How to fertilise pelargonium 'fair ellen'
- How to fertilise pelargonium quercifolium
- All 11687 fertilising guides in the Growli library