Getting it to bloom

Why won't my Sea Pea bloom? (and how to make it flower)

Also called Sea pea, Beach pea, Circumpolar pea, Sea vetchling (Lathyrus japonicus).

More about sea pea

About Sea Pea

Lathyrus japonicus · also called Sea pea, Beach pea · flowering

Lathyrus japonicus is a trailing perennial legume with a circumpolar distribution, found on coastal shingle, sand dunes, and gravelly beaches across northern Europe (including the UK), North America, and northern Asia. It produces attractive blue-green pinnate leaves with tendrils and clusters of purple to lilac-pink pea flowers in summer, followed by grey-green pods. A nitrogen-fixer, it helps build soil fertility in bare coastal substrates; the most important care point is to provide full sun and sharp drainage and avoid moving established plants, as the deep root system resents disturbance. The seeds contain the neurotoxic amino acid beta-aminopropionitrile (BAPN) and the whole genus Lathyrus is considered toxic to cats, dogs, and horses.

Plant type: flowering

The reasons sea pea isn't blooming

Almost every non-blooming sea pea traces back to one of these, roughly in order of how common they are:

Too little sun — most of these need full sun (or very bright light) to flower well; shade gives leaves, not blooms.
Too much nitrogen feed, driving lush foliage at the expense of flowers (very common with general or lawn feeds).
The plant has not been deadheaded, so it stops flowering once it sets seed.
Irregular watering — drought or waterlogging at the budding stage makes buds abort.
It is still too young or was checked by a transplant and is rebuilding before flowering.

Feeding sea pea a high-nitrogen general feed and growing it in too little sun — you get a big leafy plant and almost no flowers.

The fix — how to get sea pea to flower

Maximise sun. Give sea pea the sunniest spot you have — for most bedding and fruiting plants, more direct light directly means more flowers.
Switch the feed. Move off high-nitrogen feeds and use a higher-potassium "bloom" or tomato-type feed as it comes into flower.
Deadhead regularly. Remove spent flowers often to keep it producing more rather than stopping to set seed.
Water consistently. Keep moisture even through budding and flowering — drought-then-flood swings make buds drop.

Light and feeding do most of the heavy lifting here. Dial in the spot with the light guide for sea pea and get the feeding right with the sea pea fertilising schedule — the wrong feed (too much nitrogen) is one of the most common silent reasons a healthy plant makes leaves instead of flowers.

Bloom season and what to expect

Sea Pea flowers across its growing season (mostly summer) and, kept fed and deadheaded, can bloom for many weeks or right up to frost.

Post-bloom care so it flowers again

Deadhead, keep feeding lightly, and many will rebloom; collect seed from the best plants at the end of the season if you want to grow them again.

For everything else this plant needs day to day, see the full sea pea care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Sea Pea blooming — frequently asked questions

Why won't my sea pea flower?

Sea Pea blooms on the season's growth given enough sun, warmth and the right feed — there is no cold or photoperiod trick, just good growing conditions and a bloom-leaning feed. The most common reason it is not happening: Too little sun — most of these need full sun (or very bright light) to flower well; shade gives leaves, not blooms.

How do I make sea pea bloom?

Give sea pea the sunniest spot you have — for most bedding and fruiting plants, more direct light directly means more flowers. Move off high-nitrogen feeds and use a higher-potassium "bloom" or tomato-type feed as it comes into flower.

When does sea pea normally bloom?