🌸 How Long Do Sweet Peas Flower For? | UK Growing Guide

🇬🇧 Introduction: Sweet Peas in Full Bloom

Sweet peas (Lathyrus odoratus) are a staple of British summer gardens, loved for their vibrant colours and powerful fragrance. But one of the most common questions among gardeners is: how long do sweet peas flower for? The answer depends on when you sow them, how well you maintain them, and whether you keep picking the blooms. Let’s break it down for UK conditions.

🌼 Typical Flowering Duration in the UK

In general, sweet peas flower for 8 to 12 weeks, with the main blooming window falling between late May and early August, depending on when you sow.

With proper care, you can extend the flowering season well into late summer.

🔁 Key Factors That Affect Flowering Time

1. Sowing Time

• Autumn sowing (under cover) gives a head start and earlier flowers.
• Spring sowing is still reliable but flowers arrive later.

2. Deadheading & Picking

• The golden rule: the more you pick, the more they bloom.
• Remove fading blooms and seed pods to stop the plant from setting seed.

3. Sunlight

• Full sun = maximum blooms.
• In shadier spots, flowering may be reduced or delayed.

4. Feeding & Watering

• Feed with high-potash fertiliser (like tomato feed) every 1–2 weeks once flowering begins.
• Keep well-watered in dry spells for non-stop blooming.

5. Weather Conditions

• A cool summer can slightly extend the season.
• Hot, dry spells may shorten it unless plants are watered consistently.

✂️ How to Keep Sweet Peas Flowering Longer

• Pick daily if possible – especially during peak bloom weeks.
• Remove any forming seed pods immediately.
• Mulch in early summer to retain moisture and prevent stress.
• Feed regularly with liquid fertiliser to promote more flower buds.

🧤 When Do Sweet Peas Stop Flowering?

• Flowering usually slows by late July to early August, particularly in spring-sown varieties.
• Plants naturally decline once they begin forming seeds or if stressed by heat or drought.
• You can pull up and compost plants once flowering ceases or let a few pods form for seed collection.

🌿 Can You Extend the Season?

Yes—try succession sowing (e.g. early March and late April) to stagger flowering times.

💬 Top 10 FAQs

1. How long do sweet peas flower for in the UK?
Typically 8–12 weeks, depending on care and sowing time.

2. Can sweet peas flower into September?
Rarely. Flowering usually tapers off in August unless sown very late or carefully maintained.

3. Will picking the flowers really prolong blooming?
Yes—regular picking prevents seed pod formation, encouraging the plant to keep flowering.

4. When do sweet peas start to flower?
From late May to June, depending on sowing method.

5. Do sweet peas flower in partial shade?
They’ll survive, but blooms will be fewer and later than those in full sun.

6. Do all sweet peas have the same bloom duration?
No—some varieties are bred for longer flowering. Check seed packets for details.

7. How often should I feed sweet peas?
Once flowering starts, every 7–14 days with a potassium-rich feed.

8. Can you get a second flush of flowers?
Yes—if regularly deadheaded and fed, plants often keep producing well into August.

9. What causes early decline in flowering?
Neglecting to pick flowers, drought, lack of nutrients, or letting seeds form.

10. Should I sow again mid-summer?
It’s too late—sweet peas need time to develop before flowering. Best to sow again in autumn or early spring.

📋 Quick Tips for Prolonged Blooming

• ✅ Sow in autumn for early blooms
• ✅ Keep picking to extend flowering
• ✅ Feed with potash-rich fertiliser
• ✅ Water regularly in dry periods
• ✅ Mulch to conserve moisture

🌟 Conclusion

Sweet peas bloom for around 8–12 weeks in the UK, with the flowering season influenced by sowing time, care, and climate. By sowing early, feeding well, and picking daily, you can enjoy their fragrance and colour from late spring to mid-summer—making them one of the most rewarding annuals for allotments and gardens alike.