Loved by gardeners for their lovely fragrance and bright, pretty flowers, sweet peas are one of the nation's favourite summer flowers.
They make an enchanting addition to an English cottage garden, winding around fences and trellises, and are wonderfully easy to grow from seed.
Sweet peas do require a little extra attention, however, to ensure they bloom throughout the summer season — and this doesn't stop once they've flowered.
Sweet peas typically bloom from June to September, reaching their peak in late June and July – but there are a few things you can do to not only achieve a (potential) second flush of flowers, but better ones next year too.
From the correct way to deadhead to when to keep seeds back for next year, we asked an expert about the best ways to handle sweet peas after flowering.
What should you do with sweet peas after flowering?
Once your sweet peas are in full bloom, there are some simple steps you can take to preserve their health and ensure you have beautiful flowers next year.
Be vigilant with deadheading
Deadheading is particularly important for maintaining sweet peas. "Once sweet peas have finished flowering, the first thing I recommend is continuing to deadhead regularly if there are still blooms appearing," Luke explains.
"Sweet peas are prolific flowerers, but once they start putting energy into seed production, flowering quickly slows down. Removing spent flowers and seed pods helps prolong the display for as long as possible."
Cut plants down to the base (and leave the roots)
Towards the end of the season, when flowering has completely finished, cut the plants down at the base and add the healthy growth to your compost heap, advises Luke.
He says: "Leave the roots in the ground if you can, as sweet peas are legumes and help improve soil fertility by fixing nitrogen.
"It's also a good opportunity to enrich the soil with compost or well-rotted organic matter, ready for next year's planting."
Hold back some seeds for next year
"If you've grown a variety you particularly love, you can allow a few pods to mature and dry on the plant before collecting the seeds," Luke explains.
"Store them somewhere cool and dry over winter, and you'll have a ready supply for next season."
Top tips to make your sweet peas last longer:
To help your plant grow stronger, Luke recommends:
- Don't forget to check the health of the soil your sweet peas are planted in. "The strongest sweet peas usually start with good preparation," Luke explains. "They thrive in fertile, well-drained soil, so I always suggest working plenty of compost or organic matter into the planting area before they go in. Strong roots are the foundation of strong plants."
- Consistent watering is important for all plants in summer, and even more so with sweet peas. "Sweet peas don't like to dry out, particularly during warm weather, and irregular watering can lead to weaker growth and fewer flowers," Luke explains. "A thick layer of mulch around the base helps retain moisture and keeps the root zone cool."
- It's important to protect delicate sweet peas from the elements. "As the plants grow, tie them into supports little and often," suggests Luke. "This prevents stems from becoming damaged by wind and encourages them to put energy into producing healthy foliage and flowers rather than repairing themselves. Pinching out the growing tips when plants are young can also promote bushier growth and more flowering stems later in the season."
- Remember to feed sweet peas every couple of weeks. "Finally, feeding every couple of weeks with a high-potash [high potassium] fertiliser once flowering begins can make a noticeable difference," Luke advises. "It encourages stronger growth and a longer-lasting floral display, helping sweet peas perform at their very best."
Summer gardening edit
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