Annual
Sweet pea
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Flowers | Flowers in June | Flowers in July | Flowers in August | Flowers in September | ||||||||
| Plant | Plant in March | Plant in April | Plant in May | |||||||||
| Looks good | Looks good in June | Looks good in July | Looks good in August | Looks good in September |
Overview
Few flowers match sweet peas for scent, and a jug on the kitchen table is a summer ritual for many gardeners. They are hardy annual climbers that cling by tendrils. Grandiflora and heritage varieties like 'Cupani' and 'Matucana' carry the strongest perfume, while Spencer types, such as 'Gwendoline' or 'Mollie Rilstone', have larger, frilled flowers on long stems for cutting. Dwarf 'Cupid' types trail from hanging baskets.
Where to grow sweet pea
Grow them up a wigwam of canes, a hazel obelisk or netting, in sun and rich soil. They are perfect on an allotment fence or in a large tub by the back door. Hot, dry spots shorten the flowering season.
Planting
Sow two seeds per root trainer or deep pot from October to November and overwinter in a cold frame, or sow in a cool greenhouse in February and March. Plant out in April, after hardening off. You can also sow directly into the ground in April or May for later flowers.
Care through the year
Spring
Pinch out the tips when young plants have three or four pairs of leaves to encourage sideshoots. Tie stems loosely to supports until the tendrils take hold.
Summer
Water deeply in dry weather, mulch, feed weekly with a tomato fertiliser and cut flowers every two or three days. Remove any seed pods.
Autumn
Sow seed for next year. Add spent plants to the compost heap; roots enrich the soil with nitrogen.
Winter
Keep autumn-sown seedlings cool, bright and fairly dry, ventilating cold frames on mild days.
Pruning
No pruning as such, but pick flowers and snap off seed pods regularly so plants keep making new buds.
Propagation
Grow from seed only. Some gardeners chip or soak hard-coated seed overnight before sowing, though many varieties germinate well without. Save seed from your favourites by leaving a few pods to ripen at the end of the season.
Common problems
Mice eat seeds, so protect trays. Slugs damage seedlings. Aphids and powdery mildew build up in hot, dry summers; consistent watering helps. Bud drop is usually caused by cold nights or sudden dry soil. The seeds are poisonous to people too.
Guides to the problems most likely to affect sweet pea:
Something else wrong? Diagnose it by symptom.
Month-by-month reminders
Jobs for this plant come round in March, April and May. Each month page lists everything else worth doing in the garden at the same time.
Related plants
Sources
Botanical names follow Kew's Plants of the World Online; growing attributes were checked against the references below. Text is our own. See our editorial policy.