Fertilising guide
How to fertilise Sickle-leaved Hare's-ear (Bupleurum falcatum)— schedule & NPK
Also called Sickle-leaved Hare's-ear, Sickle Hare's Ear, Falcate Thorow-wax.
More about sickle-leaved hare's-ear
About Sickle-leaved Hare's-ear
Bupleurum falcatum · also called Sickle-leaved Hare's-ear, Sickle Hare's Ear · flowering
Bupleurum falcatum is an upright perennial in the carrot family (Apiaceae), native to dry, calcareous grasslands and stony slopes across central and southern Europe, with a handful of historical sites in Essex in the UK where it is now extremely rare. It bears small compound umbels of yellow-green flowers on branching stems from midsummer into autumn, and is highly tolerant of drought and poor, stony soil once established. The most important care requirement is sharp drainage — waterlogged conditions are fatal. It is not listed as toxic by the ASPCA; however, some Apiaceae relatives are toxic, so treat with caution.
Growth habit: Upright, branching perennial with sickle-shaped (falcate) leaves and flat-topped yellow-green umbels on wiry stems.
What fertiliser sickle-leaved hare's-ear actually wants — and why
Sickle-leaved Hare's-ear 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 sickle-leaved hare's-ear: 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 sickle-leaved hare's-ear, 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 sickle-leaved hare's-ear:
Apply a light balanced feed in spring if soil is particularly poor; avoid high-nitrogen fertilisers, which cause lax, floppy growth and reduce drought tolerance. Treat that as sparingly through the growing season 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 sickle-leaved hare's-ear 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 sickle-leaved hare's-ear
Half strength is the safe default for sickle-leaved hare's-ear — 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 sickle-leaved hare's-ear first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the sickle-leaved hare's-ear watering schedule.
Signs you are over-feeding sickle-leaved hare's-ear
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for sickle-leaved hare's-ear:
- 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 sickle-leaved hare's-ear
- 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 sickle-leaved hare's-ear care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Flush the pot of sickle-leaved hare's-ear 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 sickle-leaved hare's-ear
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 sickle-leaved hare's-ear — frequently asked questions
What fertiliser does sickle-leaved hare's-ear 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. Sickle-leaved Hare's-ear 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 sickle-leaved hare's-ear?
Apply a light balanced feed in spring if soil is particularly poor; avoid high-nitrogen fertilisers, which cause lax, floppy growth and reduce drought tolerance. Apply a light balanced feed in spring if soil is particularly poor; avoid high-nitrogen fertilisers, which cause lax, floppy growth and reduce drought tolerance. Treat that as sparingly through the growing season 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 sickle-leaved hare's-ear?
Half strength is the safe default for sickle-leaved hare's-ear — houseplant feeds are formulated strong, and the diluted dose is gentler on the roots while still ample for foliage.
What does over-feeding sickle-leaved hare's-ear 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 sickle-leaved hare's-ear 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 sickle-leaved hare's-ear?
Flush the pot of sickle-leaved hare's-ear 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
- Sickle-leaved Hare's-ear care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water sickle-leaved hare's-ear — 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 hairy woodrush
- How to fertilise giant sacaton
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- All 10153 fertilising guides in the Growli library