Fertilising guide
How to fertilise Prostrate Rosemary (Salvia rosmarinus 'Prostratus')— schedule & NPK
Also called Creeping Rosemary, Trailing Rosemary.
More about prostrate rosemary
About Prostrate Rosemary
Salvia rosmarinus 'Prostratus' · also called Creeping Rosemary, Trailing Rosemary · herb
Prostrate rosemary is a low, spreading form of culinary rosemary that cascades over walls, banks, and pot edges, carrying the same needle leaves, blue spring flowers, and aromatic, kitchen-ready foliage. It loves full sun and sharp drainage, tolerates drought, but is less cold-hardy than upright cultivars and dislikes wet winter soil.
Growth habit: Low, trailing, woody evergreen that spreads sideways and cascades downward rather than growing upright; ideal for raised beds, retaining walls, and hanging containers.
What fertiliser prostrate rosemary actually wants — and why
Prostrate Rosemary 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 prostrate rosemary: 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 prostrate rosemary, 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 prostrate rosemary:
Light feeder. A topdress of compost in spring suits ground-grown plants; container plants benefit from a balanced liquid feed every 4-6 weeks in the growing season. Over-feeding produces soft growth that is less aromatic and more prone to cold and rot. In practice: a spring compost top-dress at most, and otherwise leave prostrate rosemary 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 prostrate rosemary 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 prostrate rosemary
As weak as it gets for prostrate rosemary, 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 prostrate rosemary first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the prostrate rosemary watering schedule.
Signs you are over-feeding prostrate rosemary
Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for prostrate rosemary:
- 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 prostrate rosemary
- 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 prostrate rosemary care brief covers soil, humidity and the common problems for this species.
Flushing and leaching the salts
Over-feeding is so unlikely with prostrate rosemary 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 prostrate rosemary
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 prostrate rosemary. 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 prostrate rosemary — frequently asked questions
What fertiliser does prostrate rosemary 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. Prostrate Rosemary 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 prostrate rosemary?
Light feeder. A topdress of compost in spring suits ground-grown plants; container plants benefit from a balanced liquid feed every 4-6 weeks in the growing season. Over-feeding produces soft growth that is less aromatic and more prone to cold and rot. Light feeder. A topdress of compost in spring suits ground-grown plants; container plants benefit from a balanced liquid feed every 4-6 weeks in the growing season. Over-feeding produces soft growth that is less aromatic and more prone to cold and rot. In practice: a spring compost top-dress at most, and otherwise leave prostrate rosemary unfed — lean, sharp-draining soil is exactly what concentrates its flavour.
What strength of feed for prostrate rosemary?
As weak as it gets for prostrate rosemary, 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 prostrate rosemary 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 prostrate rosemary 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 prostrate rosemary?
Over-feeding is so unlikely with prostrate rosemary 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
- Prostrate Rosemary care — the full brief (light, soil, humidity, problems, pet safety)
- How often to water prostrate rosemary — 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 1284 fertilising guides in the Growli library