Fertilising guide
How to fertilise Begonia sutherlandii (Begonia sutherlandii)— schedule & NPK
Also called sutherland's begonia, orange begonia, trailing tuberous begonia.
More about begonia sutherlandii
About Begonia sutherlandii
Begonia sutherlandii · also called sutherland's begonia, orange begonia · flowering
Begonia sutherlandii is a trailing tuberous begonia from South African mountain slopes, prized for cascades of bright orange flowers from summer into autumn over slender red stems and toothed, lance-shaped green leaves. It cascades beautifully from hanging baskets, dies back to a tuber for winter, and reproduces freely from tiny leaf-axil bulbils.
Growth habit: Trailing, well-branched tuberous perennial with arching red stems; cascades over basket and pot edges, flowers prolifically June to October, then dies back to a dormant tuber.
What fertiliser begonia sutherlandii actually wants — and why
Begonia sutherlandii is a heavy-blooming flower with a big appetite — a regular high-potash feed through the season is what drives a long, dense display.
A high-potassium ("high-potash") flowering feed — tomato-style or a dedicated bloom/rose feed. Potassium powers flowering; a high-nitrogen feed gives you a leafy plant with disappointing bloom.
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 begonia sutherlandii: 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 begonia sutherlandii, 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 begonia sutherlandii:
Feed every two weeks through the growing season with a high-potash liquid feed to support continuous flowering; stop as the plant enters dormancy in autumn. For a hungry bloomer that means feeding regularly — sparingly through the growing season — right through flowering across the main season (spring through early autumn), tapering as blooming ends.
The dormant-season rule matters more than the exact interval: skip feeding entirely when begonia sutherlandii 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 begonia sutherlandii
Follow the flowering-feed label rate for begonia sutherlandii, or half strength if feeding very frequently. These plants genuinely use the nutrients — under-feeding shows up fast as a thin display.
Feeding always goes onto already-damp soil, never dry roots — water begonia sutherlandii first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the begonia sutherlandii watering schedule.
Signs you are over-feeding begonia sutherlandii
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for begonia sutherlandii:
- Lots of lush leaves but few flowers (too much nitrogen).
- Scorched leaf edges and salt crust from too-strong or too-frequent feeds.
- Soft, sappy growth prone to aphids and mildew.
Signs you are under-feeding begonia sutherlandii
- Sparse, small, short-lived flowers and pale foliage.
- A tired plant that stops blooming early in the season.
- Weak growth and poor repeat-flowering after the first flush.
If the symptoms point at watering, light or roots rather than nutrition, the full begonia sutherlandii care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Container-grown begonia sutherlandii accumulates feed salts fast with frequent feeding — water until it drains each time and flush pots with plain water every few weeks to prevent scorch.
Organic vs synthetic feeds for begonia sutherlandii
Organic options
A liquid comfrey or seaweed feed (naturally potassium-rich) plus compost or well-rotted manure as a mulch. UK: comfrey feed, organic Tomorite, or rose feed; US: Espoma Rose-tone or Neptune's Harvest. Feeds and improves soil.
Synthetic / liquid feeds
A high-potash flowering feed on a regular cadence — UK: Tomorite (Levington), Phostrogen or a specialist rose feed; US: Miracle-Gro Bloom Booster or a rose food. Fast, reliable bloom response.
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 begonia sutherlandii — frequently asked questions
What fertiliser does begonia sutherlandii need?
A high-potassium ("high-potash") flowering feed — tomato-style or a dedicated bloom/rose feed. Potassium powers flowering; a high-nitrogen feed gives you a leafy plant with disappointing bloom. Begonia sutherlandii is a heavy-blooming flower with a big appetite — a regular high-potash feed through the season is what drives a long, dense display.
How often should I feed begonia sutherlandii?
Feed every two weeks through the growing season with a high-potash liquid feed to support continuous flowering; stop as the plant enters dormancy in autumn. Feed every two weeks through the growing season with a high-potash liquid feed to support continuous flowering; stop as the plant enters dormancy in autumn. For a hungry bloomer that means feeding regularly — sparingly through the growing season — right through flowering across the main season (spring through early autumn), tapering as blooming ends.
What strength of feed for begonia sutherlandii?
Follow the flowering-feed label rate for begonia sutherlandii, or half strength if feeding very frequently. These plants genuinely use the nutrients — under-feeding shows up fast as a thin display.
What does over-feeding begonia sutherlandii look like?
Lots of lush leaves but few flowers (too much nitrogen). Scorched leaf edges and salt crust from too-strong or too-frequent feeds. Soft, sappy growth prone to aphids and mildew. Using a high-nitrogen general feed on begonia sutherlandii is the headline mistake — you grow a big leafy plant with few flowers. The second is simply under-feeding a genuinely hungry bloomer and getting a sparse, short display.
Should I flush the soil of begonia sutherlandii?
Container-grown begonia sutherlandii accumulates feed salts fast with frequent feeding — water until it drains each time and flush pots with plain water every few weeks to prevent scorch.
Keep reading
- Begonia sutherlandii care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water begonia sutherlandii — 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 peace lily
- How to fertilise bird of paradise
- How to fertilise hoya
- All 2464 fertilising guides in the Growli library