Fertilising guide
How to fertilise Bougainvillea spectabilis (Bougainvillea spectabilis)— schedule & NPK
Also called great bougainvillea, paper flower.
More about bougainvillea spectabilis
About Bougainvillea spectabilis
Bougainvillea spectabilis · also called great bougainvillea, paper flower · tropical
Great bougainvillea is a thorny, evergreen tropical climber from South America whose vivid magenta, papery bracts surround tiny white true flowers. It blooms hardest in full sun with sparse water — drought stress triggers flowering. Frost-tender, it is grown outdoors in warm climates or under glass in cool ones. Thorns and irritant sap make it best kept away from pets.
Growth habit: Vigorous evergreen woody scrambling climber armed with sharp thorns; needs tying in or training to a support
Watch for — Leaves but no bracts: Too little light, overwatering or too much nitrogen — give maximum sun, keep it on the dry side and feed high-potash.
What fertiliser bougainvillea spectabilis actually wants — and why
Bougainvillea spectabilis 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 bougainvillea spectabilis: 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 bougainvillea spectabilis, 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 bougainvillea spectabilis:
Feed every 2-3 weeks in the growing season with a high-potash fertiliser (such as a tomato feed) to maximise bracts; avoid high-nitrogen feeds, which drive leaf and stem at the expense of colour. Stop feeding in winter. Treat that as every 2-3 weeks 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 bougainvillea spectabilis 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 bougainvillea spectabilis
Half strength is the safe default for bougainvillea spectabilis — 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 bougainvillea spectabilis first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the bougainvillea spectabilis watering schedule.
Signs you are over-feeding bougainvillea spectabilis
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for bougainvillea spectabilis:
- 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 bougainvillea spectabilis
- 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 bougainvillea spectabilis care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of bougainvillea spectabilis 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 bougainvillea spectabilis
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 bougainvillea spectabilis — frequently asked questions
What fertiliser does bougainvillea spectabilis 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. Bougainvillea spectabilis 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 bougainvillea spectabilis?
Feed every 2-3 weeks in the growing season with a high-potash fertiliser (such as a tomato feed) to maximise bracts; avoid high-nitrogen feeds, which drive leaf and stem at the expense of colour. Stop feeding in winter. Feed every 2-3 weeks in the growing season with a high-potash fertiliser (such as a tomato feed) to maximise bracts; avoid high-nitrogen feeds, which drive leaf and stem at the expense of colour. Stop feeding in winter. Treat that as every 2-3 weeks 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 bougainvillea spectabilis?
Half strength is the safe default for bougainvillea spectabilis — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding bougainvillea spectabilis 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 bougainvillea spectabilis 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 bougainvillea spectabilis?
Flush the pot of bougainvillea spectabilis 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
- Bougainvillea spectabilis care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water bougainvillea spectabilis — 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 monstera
- How to fertilise pothos
- How to fertilise fiddle leaf fig
- All 3899 fertilising guides in the Growli library