Fertilising guide
How to fertilise Tree philodendron (Thaumatophyllum bipinnatifidum)— schedule & NPK
Also called lacy tree philodendron, split-leaf philodendron (large), horsehead philodendron.
About Tree philodendron
Thaumatophyllum bipinnatifidum · also called lacy tree philodendron, split-leaf philodendron (large) · tropical
Tree philodendron (formerly Philodendron selloum) is a large clumping aroid from South America with deeply lobed glossy leaves. It develops a thick trunk over time. Mildly toxic to pets due to insoluble calcium oxalates and best suited to larger rooms.
Thaumatophyllum bipinnatifidum (long sold as Philodendron selloum / bipinnatifidum), native to subtropical rainforests of southern Brazil, Bolivia, Argentina and Paraguay.
A genuine heavy feeder for a philodendron: monthly balanced (or higher-nitrogen) liquid feed at full strength through spring and summer produces noticeably larger, more deeply lobed leaves.
Growth habit: Large clumping aroid with thick trunk
Watch for — Small new leaves: Insufficient light or under-feeding.
Sources: missouribotanicalgarden.org, plants.ces.ncsu.edu, aspca.org
What fertiliser tree philodendron actually wants — and why
Tree philodendron is a genuinely hungry tropical — in bright warmth it pushes growth fast and rewards a regular half-strength balanced feed all season.
A balanced liquid feed (even N-P-K) or a slightly nitrogen-leaning foliage feed — this is a big-leaved foliage plant putting on real size, so it wants steady nitrogen for lush leaves, not a bloom 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 tree philodendron: 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 tree philodendron, 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 tree philodendron:
Balanced liquid feed at half strength monthly in growing season. For a fast grower like this that means feeding regularly — about monthly — right through spring through early autumn (roughly March to September), tapering off only as light drops in autumn.
The dormant-season rule matters more than the exact interval: skip feeding entirely when tree philodendron 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 tree philodendron
Half strength every feed is the sweet spot for tree philodendron: frequent enough to fuel fast growth, dilute enough that it never scorches even when you feed often.
Feeding always goes onto already-damp soil, never dry roots — water tree philodendron first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the tree philodendron watering schedule.
Signs you are over-feeding tree philodendron
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for tree philodendron:
- Brown, scorched leaf tips and margins despite correct watering.
- A white salt crust on the soil or around the pot edge.
- Sudden leaf yellowing and drop shortly after a strong feed.
- Soft, weak, over-stretched growth that cannot support itself.
Signs you are under-feeding tree philodendron
- New leaves coming in noticeably smaller than older ones.
- Pale, yellow-green older leaves and slow growth through peak summer.
- A general loss of vigour and gloss in a plant that should be racing away.
If the symptoms point at watering, light or roots rather than nutrition, the full tree philodendron care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Because you feed often, salts accumulate faster — flush the pot of tree philodendron with plain water until it drains freely roughly every month through the feeding season to keep the root zone clean.
Organic vs synthetic feeds for tree philodendron
Organic options
A diluted seaweed or fish-and-seaweed feed plus a yearly top-dress of worm castings supports fast growth without burn risk. UK: Westland seaweed or Baby Bio Organic; US: Neptune's Harvest or Espoma Indoor!.
Synthetic / liquid feeds
A balanced houseplant liquid at half strength applied frequently — UK: Baby Bio, Phostrogen or Westland Houseplant Feed; US: Miracle-Gro Indoor Plant Food or Dyna-Gro Foliage-Pro for steady leafy growth.
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 tree philodendron — frequently asked questions
What fertiliser does tree philodendron need?
A balanced liquid feed (even N-P-K) or a slightly nitrogen-leaning foliage feed — this is a big-leaved foliage plant putting on real size, so it wants steady nitrogen for lush leaves, not a bloom formula. Tree philodendron is a genuinely hungry tropical — in bright warmth it pushes growth fast and rewards a regular half-strength balanced feed all season.
How often should I feed tree philodendron?
Balanced liquid feed at half strength monthly in growing season. Balanced liquid feed at half strength monthly in growing season. For a fast grower like this that means feeding regularly — about monthly — right through spring through early autumn (roughly March to September), tapering off only as light drops in autumn.
What strength of feed for tree philodendron?
Half strength every feed is the sweet spot for tree philodendron: frequent enough to fuel fast growth, dilute enough that it never scorches even when you feed often.
What does over-feeding tree philodendron look like?
Brown, scorched leaf tips and margins despite correct watering. A white salt crust on the soil or around the pot edge. Sudden leaf yellowing and drop shortly after a strong feed. Soft, weak, over-stretched growth that cannot support itself. The mistake here is the opposite of most houseplants: under-feeding a fast tropical in peak season starves it, leaving small, pale new leaves and slow growth — but full-strength doses still burn it, so feed often and weak, not occasionally and strong.
Should I flush the soil of tree philodendron?
Because you feed often, salts accumulate faster — flush the pot of tree philodendron with plain water until it drains freely roughly every month through the feeding season to keep the root zone clean.
Keep reading
- Tree philodendron care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water tree philodendron — 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 200 fertilising guides in the Growli library