Fertilising guide

How to fertilise Rock Jasmine (Androsace sarmentosa)— schedule & NPK

Also called Rock Jasmine, Sarmentose Androsace.

More about rock jasmine

About Rock Jasmine

Androsace sarmentosa · also called Rock Jasmine, Sarmentose Androsace · flowering

Rock Jasmine is a charming, mat-forming alpine perennial from the Himalayas and western China. Silvery-hairy rosettes spread by stolons to form wide colonies, smothered in spring and early summer with heads of deep pink to rose flowers with yellow eyes. An excellent choice for rock gardens, scree beds, and stone troughs; fully frost-hardy.

Growth habit: Stoloniferous mat-forming perennial; spreads by runners producing daughter rosettes

What fertiliser rock jasmine actually wants — and why

Rock Jasmine flowers best on poor soil — feed it and you get a lush leafy plant with very few blooms, the exact opposite of what you want.

Little or nothing. Rich, especially nitrogen-rich, soil pushes foliage at the expense of flowers in this plant — lean ground is the technique, not a deficiency.

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 rock jasmine: 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 rock jasmine, 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 rock jasmine:

Feed lightly with a balanced, low-nitrogen fertiliser once in early spring. Avoid overfeeding, which promotes lush, disease-prone growth at the expense of flowers. A grit top-dressing in lieu of heavy fertilising helps maintain soil structure. In practice: no routine feeding at all for rock jasmine — at most a thin compost mulch for soil structure, never a flowering or nitrogen feed.

The dormant-season rule matters more than the exact interval: skip feeding entirely when rock jasmine 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 rock jasmine

None is the correct answer for rock jasmine. The flower-versus-foliage trade-off is the whole point: hold back and you get the display.

Feeding always goes onto already-damp soil, never dry roots — water rock jasmine first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the rock jasmine watering schedule.

Signs you are over-feeding rock jasmine

Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for rock jasmine:

Abundant leafy growth and very few flowers (the classic over-rich symptom).
Soft, floppy stems and a sprawling, leafy habit.
Scorched edges and salt crust if it has been fed in a container.

Signs you are under-feeding rock jasmine

Effectively never an issue — these plants flower on poverty.
Only on genuinely dead soil: weak, thin growth and few blooms.
A short-lived plant in completely spent container compost.

If the symptoms point at watering, light or roots rather than nutrition, the full rock jasmine care brief covers soil, humidity and the common problems for this species.

Flushing and leaching the salts

If rock jasmine has accidentally been fed and is all leaf, a plain-water flush plus a move to leaner soil resets it; otherwise no flushing is needed because you are not feeding it.

Organic vs synthetic feeds for rock jasmine

Organic options

A thin compost mulch for soil structure is the absolute most; mostly, give it nothing. UK/US: leave it lean — no manure, no liquid feed. Poor soil is the active ingredient here.

Synthetic / liquid feeds

None. Synthetic feeds, particularly anything with appreciable nitrogen, directly suppress flowering in rock jasmine.

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 rock jasmine — frequently asked questions

What fertiliser does rock jasmine need?

Little or nothing. Rich, especially nitrogen-rich, soil pushes foliage at the expense of flowers in this plant — lean ground is the technique, not a deficiency. Rock Jasmine flowers best on poor soil — feed it and you get a lush leafy plant with very few blooms, the exact opposite of what you want.

How often should I feed rock jasmine?

Feed lightly with a balanced, low-nitrogen fertiliser once in early spring. Avoid overfeeding, which promotes lush, disease-prone growth at the expense of flowers. A grit top-dressing in lieu of heavy fertilising helps maintain soil structure. Feed lightly with a balanced, low-nitrogen fertiliser once in early spring. Avoid overfeeding, which promotes lush, disease-prone growth at the expense of flowers. A grit top-dressing in lieu of heavy fertilising helps maintain soil structure. In practice: no routine feeding at all for rock jasmine — at most a thin compost mulch for soil structure, never a flowering or nitrogen feed.

What strength of feed for rock jasmine?