Getting it to bloom

Why won't my Spencer Mixed sweet pea bloom? (and how to make it flower)

Also called Spencer Mixed sweet pea, Sweet pea, Spenser sweet pea (Lathyrus odoratus 'Spencer Mixed').

More about spencer mixed sweet pea

About Spencer Mixed sweet pea

Lathyrus odoratus 'Spencer Mixed' · also called Spencer Mixed sweet pea, Sweet pea · flowering

Spencer Mixed sweet pea is the classic large-flowered, intensely fragrant climbing annual, producing ruffled blooms in mixed shades of white, pink, lilac, mauve, and purple from early summer. It climbs to 1.8–2.5 m and needs cool roots, a support structure, and regular picking to keep flowering. Seeds and pods are toxic — do not eat.

Plant type: flowering

Watch for — Bud drop: Flower buds fail to develop or drop off before opening, usually caused by drought stress, sudden temperature swings, or irregular watering. Maintain consistent soil moisture, mulch roots, and ensure plants are not root-bound in containers.

The reasons spencer mixed sweet pea isn't blooming

Almost every non-blooming spencer mixed sweet 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 spencer mixed sweet 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 spencer mixed sweet pea to flower

Maximise sun. Give spencer mixed sweet 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 spencer mixed sweet pea and get the feeding right with the spencer mixed sweet 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

Spencer Mixed sweet 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 spencer mixed sweet pea care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Spencer Mixed sweet pea blooming — frequently asked questions

Why won't my spencer mixed sweet pea flower?

Spencer Mixed sweet 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 spencer mixed sweet pea bloom?

Give spencer mixed sweet 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 spencer mixed sweet pea normally bloom?