Fertilising guide
How to fertilise Motherwort (Leonurus cardiaca)— schedule & NPK
Also called motherwort, throw-wort, lion's ear.
More about motherwort
About Motherwort
Leonurus cardiaca · also called motherwort, throw-wort · herb
Motherwort is a hardy, upright perennial in the mint family with deeply lobed leaves and whorls of small pink-purple flowers prickly with spiny bracts. A traditional medicinal herb for heart and women's complaints, it is tough and undemanding, thriving in sun or part shade on most soils. It self-seeds vigorously and naturalises easily, often behaving like a weed.
Growth habit: Upright, clump-forming herbaceous perennial that self-seeds prolifically; spreads readily by seed and can naturalise into colonies.
What fertiliser motherwort actually wants — and why
Motherwort is a lean, aromatic herb — the essential-oil flavour you grow it for is strongest in poor soil, so feeding it actively makes it worse.
Little or nothing. If anything, a very weak balanced feed or a thin compost top-dress — never a rich nitrogen feed, which dilutes the aromatic oils and produces soft, bland, floppy growth.
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 motherwort: 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 motherwort, 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 motherwort:
None required; motherwort thrives without feeding, and rich conditions only increase its weedy spread. Skip fertiliser on established plants. In practice: a spring compost top-dress at most, and otherwise leave motherwort unfed — lean, sharp-draining soil is exactly what concentrates its flavour.
The dormant-season rule matters more than the exact interval: skip feeding entirely when motherwort 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 motherwort
As weak as it gets for motherwort, or none at all. The flavour-versus-growth trade-off runs the opposite way to leafy crops: restraint is the technique.
Feeding always goes onto already-damp soil, never dry roots — water motherwort first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the motherwort watering schedule.
Signs you are over-feeding motherwort
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for motherwort:
- Lush, soft, fast growth with noticeably weaker scent and flavour.
- Floppy stems, sparse essential oils, and poor cold/wet hardiness.
- Salt crust in containers and scorched leaf tips from over-feeding.
Signs you are under-feeding motherwort
- Rare — these herbs thrive on lean soil.
- Only on truly exhausted soil: pale, thin, very slow growth.
- A short-lived, weak plant in a long-spent container.
If the symptoms point at watering, light or roots rather than nutrition, the full motherwort care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Over-feeding is so unlikely with motherwort that flushing is rarely needed; if a container has had feed, a single plain-water flush and a switch to a leaner, grittier mix resets it.
Organic vs synthetic feeds for motherwort
Organic options
A thin spring mulch of garden compost or leaf-mould is the most these want. UK: a little garden compost; US: a light Espoma Garden-tone top-dress at most. Lean and gritty beats fed and rich every time.
Synthetic / liquid feeds
Generally none for motherwort. At absolute most, a very dilute balanced feed once or twice in a container; in the ground, nothing — synthetic feeds work directly against the flavour.
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 motherwort — frequently asked questions
What fertiliser does motherwort need?
Little or nothing. If anything, a very weak balanced feed or a thin compost top-dress — never a rich nitrogen feed, which dilutes the aromatic oils and produces soft, bland, floppy growth. Motherwort is a lean, aromatic herb — the essential-oil flavour you grow it for is strongest in poor soil, so feeding it actively makes it worse.
How often should I feed motherwort?
None required; motherwort thrives without feeding, and rich conditions only increase its weedy spread. Skip fertiliser on established plants. None required; motherwort thrives without feeding, and rich conditions only increase its weedy spread. Skip fertiliser on established plants. In practice: a spring compost top-dress at most, and otherwise leave motherwort unfed — lean, sharp-draining soil is exactly what concentrates its flavour.
What strength of feed for motherwort?
As weak as it gets for motherwort, or none at all. The flavour-versus-growth trade-off runs the opposite way to leafy crops: restraint is the technique.
What does over-feeding motherwort look like?
Lush, soft, fast growth with noticeably weaker scent and flavour. Floppy stems, sparse essential oils, and poor cold/wet hardiness. Salt crust in containers and scorched leaf tips from over-feeding. Feeding motherwort like a leafy vegetable is the defining mistake — rich nitrogen gives you a big, soft, fast plant whose leaves are watery and bland, with weak winter-rot resistance.
Should I flush the soil of motherwort?
Over-feeding is so unlikely with motherwort that flushing is rarely needed; if a container has had feed, a single plain-water flush and a switch to a leaner, grittier mix resets it.
Keep reading
- Motherwort care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water motherwort — 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 basil
- How to fertilise herb garden
- How to fertilise mint
- All 3899 fertilising guides in the Growli library