Fertilising guide
How to fertilise Cardinal climber (Ipomoea x multifida)— schedule & NPK
Also called Cardinal climber, Hearts and honey vine.
More about cardinal climber
About Cardinal climber
Ipomoea x multifida · also called Cardinal climber, Hearts and honey vine · flowering
Cardinal climber is a fast-growing annual vine — a hybrid of Ipomoea quamoclit and I. coccinea — with finely dissected, feathery foliage and vivid crimson trumpet flowers that are irresistible to hummingbirds. Grow in full sun on a trellis. Performs best in warm summers with consistent moisture. Seeds are toxic; handle with care.
Growth habit: Annual twining vine
Watch for — Few flowers despite healthy growth: Excess nitrogen or too-rich soil diverts energy to foliage. Switch to a phosphorus-higher fertiliser and ensure the plant receives full sun. Consistent but not excessive watering also helps.
What fertiliser cardinal climber actually wants — and why
Cardinal climber 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 cardinal climber: 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 cardinal climber, 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 cardinal climber:
Apply a balanced granular fertiliser (10-10-10) at planting. Supplement monthly with a low-nitrogen liquid feed (e.g., 5-10-10) to promote flowering. Over-fertilising, especially with nitrogen, strongly reduces blooms. Treat that as monthly 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 cardinal climber 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 cardinal climber
Half strength is the safe default for cardinal climber — 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 cardinal climber first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the cardinal climber watering schedule.
Signs you are over-feeding cardinal climber
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for cardinal climber:
- 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 cardinal climber
- 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 cardinal climber care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of cardinal climber 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 cardinal climber
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 cardinal climber — frequently asked questions
What fertiliser does cardinal climber 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. Cardinal climber 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 cardinal climber?
Apply a balanced granular fertiliser (10-10-10) at planting. Supplement monthly with a low-nitrogen liquid feed (e.g., 5-10-10) to promote flowering. Over-fertilising, especially with nitrogen, strongly reduces blooms. Apply a balanced granular fertiliser (10-10-10) at planting. Supplement monthly with a low-nitrogen liquid feed (e.g., 5-10-10) to promote flowering. Over-fertilising, especially with nitrogen, strongly reduces blooms. Treat that as monthly 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 cardinal climber?
Half strength is the safe default for cardinal climber — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding cardinal climber 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 cardinal climber 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 cardinal climber?
Flush the pot of cardinal climber 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
- Cardinal climber care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water cardinal climber — 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 chocolate orchid
- How to fertilise dipladenia (mandevilla)
- How to fertilise calendula
- All 6887 fertilising guides in the Growli library