Fertilising guide
How to fertilise Grandidier's Uncarina (Uncarina grandidieri)— schedule & NPK
Also called Grandidier's Uncarina, Sesame Tree, Madagascan Unicorn Plant.
More about grandidier's uncarina
About Grandidier's Uncarina
Uncarina grandidieri · also called Grandidier's Uncarina, Sesame Tree · tropical
Uncarina grandidieri is a striking deciduous succulent tree from Madagascar's dry spiny thickets, grown for its swollen pachycaul trunk and showy yellow flowers. It demands full sun, excellent drainage, and a dry winter rest. A rewarding specimen for collectors of Madagascan flora and arid-climate enthusiasts.
Growth habit: Deciduous pachycaul shrub or small tree with a greatly swollen water-storing trunk (caudex), sparse succulent branches, and large yellow trumpet flowers appearing before or with new leaves.
Watch for — Failure to flower: Caused by insufficient light or excessive nitrogen feeding. Move to a sunnier position and switch to a low-nitrogen, high-potash fertiliser to encourage bud set.
What fertiliser grandidier's uncarina actually wants — and why
Grandidier's Uncarina 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 grandidier's uncarina: 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 grandidier's uncarina, 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 grandidier's uncarina:
Feed once a month with a low-nitrogen, high-potassium succulent fertiliser (e.g. NPK 3-9-9) from late spring through August. Do not feed in autumn or winter during dormancy. Treat that as once a month 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 grandidier's uncarina 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 grandidier's uncarina
Half strength is the safe default for grandidier's uncarina — 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 grandidier's uncarina first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the grandidier's uncarina watering schedule.
Signs you are over-feeding grandidier's uncarina
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for grandidier's uncarina:
- 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 grandidier's uncarina
- 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 grandidier's uncarina care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of grandidier's uncarina 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 grandidier's uncarina
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 grandidier's uncarina — frequently asked questions
What fertiliser does grandidier's uncarina 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. Grandidier's Uncarina 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 grandidier's uncarina?
Feed once a month with a low-nitrogen, high-potassium succulent fertiliser (e.g. NPK 3-9-9) from late spring through August. Do not feed in autumn or winter during dormancy. Feed once a month with a low-nitrogen, high-potassium succulent fertiliser (e.g. NPK 3-9-9) from late spring through August. Do not feed in autumn or winter during dormancy. Treat that as once a month 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 grandidier's uncarina?
Half strength is the safe default for grandidier's uncarina — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding grandidier's uncarina 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 grandidier's uncarina 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 grandidier's uncarina?
Flush the pot of grandidier's uncarina 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
- Grandidier's Uncarina care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water grandidier's uncarina — 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 nepenthes tenuis
- How to fertilise nepenthes merrilliana
- How to fertilise nepenthes copelandii
- All 8452 fertilising guides in the Growli library