Fertilising guide

How to fertilise Madagascar Periwinkle (Vinca) (Catharanthus roseus)— schedule & NPK

Also called Madagascar periwinkle, Annual vinca, Rose periwinkle, Cape periwinkle, Running myrtle, Old maid.

More about madagascar periwinkle (vinca)

About Madagascar Periwinkle (Vinca)

Catharanthus roseus · also called Madagascar periwinkle, Annual vinca · flowering

Madagascar periwinkle is a heat-loving flowering annual (perennial in zones 10-11) prized for non-stop pink, white, and rose blooms through hot, dry summers. Give it full sun, fast-draining soil, and water only when the top inch dries. Toxic to dogs, cats, and horses, per the ASPCA.

Growth habit: Fast-growing, erect-to-mounding tender subshrub with glossy dark-green leaves; grown as a warm-season annual in most climates. Modern hybrids are self-cleaning and need no pinching or deadheading to keep blooming.

What fertiliser madagascar periwinkle (vinca) actually wants — and why

Madagascar Periwinkle (Vinca) is a heavy-blooming flower with a big appetite — a regular high-potash feed through the season is what drives a long, dense display.

A high-potassium ("high-potash") flowering feed — tomato-style or a dedicated bloom/rose feed. Potassium powers flowering; a high-nitrogen feed gives you a leafy plant with disappointing bloom.

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 madagascar periwinkle (vinca): 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 madagascar periwinkle (vinca), 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 madagascar periwinkle (vinca):

Feed lightly every 2-3 weeks during the growing season with a balanced liquid fertiliser, or use a slow-release feed at planting. Do not over-fertilise: lush, succulent new growth from heavy feeding is far more susceptible to blight. For a hungry bloomer that means feeding regularly — every 2-3 weeks — right through flowering across the main season (spring through early autumn), tapering as blooming ends.

The dormant-season rule matters more than the exact interval: skip feeding entirely when madagascar periwinkle (vinca) 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 madagascar periwinkle (vinca)

Follow the flowering-feed label rate for madagascar periwinkle (vinca), or half strength if feeding very frequently. These plants genuinely use the nutrients — under-feeding shows up fast as a thin display.

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

Signs you are over-feeding madagascar periwinkle (vinca)

Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for madagascar periwinkle (vinca):

Lots of lush leaves but few flowers (too much nitrogen).
Scorched leaf edges and salt crust from too-strong or too-frequent feeds.
Soft, sappy growth prone to aphids and mildew.

Signs you are under-feeding madagascar periwinkle (vinca)

Sparse, small, short-lived flowers and pale foliage.
A tired plant that stops blooming early in the season.
Weak growth and poor repeat-flowering after the first flush.

If the symptoms point at watering, light or roots rather than nutrition, the full madagascar periwinkle (vinca) care brief covers soil, humidity and the common problems for this species.

Flushing and leaching the salts

Container-grown madagascar periwinkle (vinca) accumulates feed salts fast with frequent feeding — water until it drains each time and flush pots with plain water every few weeks to prevent scorch.

Organic vs synthetic feeds for madagascar periwinkle (vinca)

Organic options

A liquid comfrey or seaweed feed (naturally potassium-rich) plus compost or well-rotted manure as a mulch. UK: comfrey feed, organic Tomorite, or rose feed; US: Espoma Rose-tone or Neptune's Harvest. Feeds and improves soil.

Synthetic / liquid feeds

A high-potash flowering feed on a regular cadence — UK: Tomorite (Levington), Phostrogen or a specialist rose feed; US: Miracle-Gro Bloom Booster or a rose food. Fast, reliable bloom response.

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 madagascar periwinkle (vinca) — frequently asked questions

What fertiliser does madagascar periwinkle (vinca) need?

A high-potassium ("high-potash") flowering feed — tomato-style or a dedicated bloom/rose feed. Potassium powers flowering; a high-nitrogen feed gives you a leafy plant with disappointing bloom. Madagascar Periwinkle (Vinca) is a heavy-blooming flower with a big appetite — a regular high-potash feed through the season is what drives a long, dense display.

How often should I feed madagascar periwinkle (vinca)?

Feed lightly every 2-3 weeks during the growing season with a balanced liquid fertiliser, or use a slow-release feed at planting. Do not over-fertilise: lush, succulent new growth from heavy feeding is far more susceptible to blight. Feed lightly every 2-3 weeks during the growing season with a balanced liquid fertiliser, or use a slow-release feed at planting. Do not over-fertilise: lush, succulent new growth from heavy feeding is far more susceptible to blight. For a hungry bloomer that means feeding regularly — every 2-3 weeks — right through flowering across the main season (spring through early autumn), tapering as blooming ends.

What strength of feed for madagascar periwinkle (vinca)?

What does over-feeding madagascar periwinkle (vinca) look like?

Lots of lush leaves but few flowers (too much nitrogen). Scorched leaf edges and salt crust from too-strong or too-frequent feeds. Soft, sappy growth prone to aphids and mildew. Using a high-nitrogen general feed on madagascar periwinkle (vinca) is the headline mistake — you grow a big leafy plant with few flowers. The second is simply under-feeding a genuinely hungry bloomer and getting a sparse, short display.

Should I flush the soil of madagascar periwinkle (vinca)?