Fertilising guide

How to fertilise Everlasting Sweet Pea (Lathyrus latifolius)— schedule & NPK

Also called Perennial sweet pea, Everlasting pea.

More about everlasting sweet pea

About Everlasting Sweet Pea

Lathyrus latifolius · also called Perennial sweet pea, Everlasting pea · flowering

The everlasting pea is a tough herbaceous perennial climber that returns yearly from a deep rootstock, throwing out winged stems hung with clusters of pink, rose or white pea flowers all summer. Unlike the annual sweet pea it is scentless but trouble-free, naturalising readily and tolerating poor soil and drought once established.

Growth habit: Herbaceous perennial tendril-climber that dies back in winter and regrows from a woody rootstock each spring; can also sprawl as groundcover.

What fertiliser everlasting sweet pea actually wants — and why

Everlasting Sweet Pea 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 everlasting sweet pea: 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 everlasting sweet pea, 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 everlasting sweet pea:

Light feeder. A spring mulch of compost is usually enough; an occasional high-potash feed boosts flowering but is rarely necessary on decent soil. For a hungry bloomer that means feeding regularly — sparingly through the growing season — 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 everlasting sweet pea 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 everlasting sweet pea

Follow the flowering-feed label rate for everlasting sweet pea, 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 everlasting sweet pea first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the everlasting sweet pea watering schedule.

Signs you are over-feeding everlasting sweet pea

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

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 everlasting sweet pea

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 everlasting sweet pea care brief covers soil, humidity and the common problems for this species.

Flushing and leaching the salts

Container-grown everlasting sweet pea 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 everlasting sweet pea

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 everlasting sweet pea — frequently asked questions

What fertiliser does everlasting sweet pea 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. Everlasting Sweet Pea 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 everlasting sweet pea?

Light feeder. A spring mulch of compost is usually enough; an occasional high-potash feed boosts flowering but is rarely necessary on decent soil. Light feeder. A spring mulch of compost is usually enough; an occasional high-potash feed boosts flowering but is rarely necessary on decent soil. For a hungry bloomer that means feeding regularly — sparingly through the growing season — right through flowering across the main season (spring through early autumn), tapering as blooming ends.

What strength of feed for everlasting sweet pea?

What does over-feeding everlasting sweet pea 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 everlasting sweet pea 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 everlasting sweet pea?