Fertilising guide

How to fertilise Cape Mallow (Anisodontea capensis)— schedule & NPK

Also called Cape Mallow, African Mallow, Dwarf Pink Hibiscus.

More about cape mallow

About Cape Mallow

Anisodontea capensis · also called Cape Mallow, African Mallow · flowering

Anisodontea capensis is a fast-growing, evergreen shrub native to the Western and Eastern Cape of South Africa, producing an almost continuous succession of small, pale to mid-pink hibiscus-like flowers from spring through autumn and into winter in mild climates. It prefers full sun and well-drained soil, and is best grown in a sheltered sunny spot outdoors or as a cool greenhouse or conservatory plant in most of the UK, as it is damaged by frost below −2°C. Tip-prune young plants to encourage bushy branching, and hard-prune in spring if plants become leggy. It is not listed in the ASPCA database, and no toxic principles are documented for Anisodontea, but a precautionary mildly-toxic rating is applied.

Growth habit: Upright to spreading, freely branching evergreen shrub with hairy stems and lobed, aromatic leaves.

Watch for — Glasshouse red spider mite: A primary pest when plants are grown under glass or in hot, dry conditions; mites cause pale, speckled foliage — maintain humidity, mist regularly, and introduce Phytoseiulus persimilis for biological control.

What fertiliser cape mallow actually wants — and why

Cape Mallow 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 cape mallow: 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 cape mallow, 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 cape mallow:

Feed monthly with a balanced liquid fertiliser during the growing season; avoid high-nitrogen feeds which promote foliage at the expense of flowers. In practice: no routine feeding at all for cape mallow — 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 cape mallow 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 cape mallow

None is the correct answer for cape mallow. 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 cape mallow first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the cape mallow watering schedule.

Signs you are over-feeding cape mallow

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

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 cape mallow

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 cape mallow care brief covers soil, humidity and the common problems for this species.

Flushing and leaching the salts

If cape mallow 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 cape mallow

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 cape mallow.

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 cape mallow — frequently asked questions

What fertiliser does cape mallow 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. Cape Mallow 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 cape mallow?

Feed monthly with a balanced liquid fertiliser during the growing season; avoid high-nitrogen feeds which promote foliage at the expense of flowers. Feed monthly with a balanced liquid fertiliser during the growing season; avoid high-nitrogen feeds which promote foliage at the expense of flowers. In practice: no routine feeding at all for cape mallow — at most a thin compost mulch for soil structure, never a flowering or nitrogen feed.

What strength of feed for cape mallow?