Updated 13/06/2025
Sweet peas are a great all rounder in the garden. With delicate flowers with a delightful fragrance and climbing habit they’re great when grown up wigwams and garden canes. Their habit makes them fantastic for any size garden, even small spaces. They lend themselves to cottage style spots. But even though they’re beautiful, there are still problems relating to pests and disease. So, these are some solutions to deal with them.
‘My sweet pea flowers are falling off’
If you’re experiencing flowers falling off sweet peas, the chances are it’s not caused by insects or disease. Instead, it’s likely to be caused by the weather and the environment.
Hot, sunny weather can lead to the soil around the plants becoming dry which can cause dropping of flowers. Both runner beans and sweat peas are prone to flower drop if the soil gets too dry.
Early in the season it’s more likely that we’ll experience warm days and cold nights which can have an impact on the plants. So, to stop this being a problem for your sweet peas, delay planting by about two weeks to reduce the likelihood of flowers dropping and, whilst waiting for weather conditions to improve, harden off the plants by placing them outside during the day and bringing them back inside before nightfall.
If there’s a temperature drop forecast, protect the young plants that are already outdoors.
Equally, ensure the water being used to give moisture isn’t icy cold because this can shock the plant and cause the flowers to drop too.
As a solution, remove any seedpods that are forming because this will direct the energy back into the plant’s growth and flowering, and keep watering deeply and well to moisten the soil.
The trick is to water first thing in the morning rather than last thing at night as on warm days that would be creating the ideal moist, warm, dark environment beloved of slugs and snails. Also ensure soil is covered with a deep layer of mulch, at least 10cm thick, which will retain moisture, insulate the roots, and suppress weeds.
‘Can I save leggy sweet peas?’
Seedlings of sweet peas might begin to grow leggy. This is when they grow upwards and have a slightly scraggly appearance rather than looking full and healthy. This can be caused by insufficient light and excess warmth. If this seems to be the problem, seedlings can be moved to a cooler and brighter spot.
However, you can also encourage side shoots to grow by pinching out the tips of the plants by snipping off the top of the stem slightly above a set of leaves. This will therefore support dense and bushier growth to make the plant more sturdy. Some people report success in making new plants from those removed tips by placing them in water until they develop ‘water roots’. Worth a try if you’re looking for extra plants.
If the sweet peas are growing on canes or trellis, the long stems can be trained along the ground and tied into a separate cane for them to grow upwards on.
‘Slugs and snails have attacked my sweet peas’
Unfortunately, young sweet pea plants are prone to slug and snail damage, but there are a few ways to control or prevent this from happening.
If you spot slugs and snails on the foliage, physically remove them by hand or using chopsticks to rid them of the area.
Alternatively, take advantage of companion planting methods by planting strong scented plants like lavender, rosemary, and fennel as a deterrent. The other option is to offer sacrificial plants that slugs and snails do like to encourage them to those rather than feasting on your sweet peas. Good examples are nasturtiums and hostas, that slugs will appreciate.
‘My sweet pea leaves are turning yellow’
If you’ve found that the leaves of your sweet peas are turning yellow, this is likely down to overwatering which has resulted in root rot. On the other hand, it could be a sign that the compost is too nutrient rich, which has led to the roots burning.
Therefore, before planting ensure the soil is well-drained rather then heavy and wet. Once planted, water as necessary to keep the compost moist but not wet. In the UK this will probably mean extra watering isn’t necessarily needed unless there are prolonged dry spells.
Top tips for growing sweet peas
- When growing sweet peas from seed, water the seedlings and young plants regularly until they are planted out and established. Mulching can help to keep the compost moist too. Placing the pots in a shallow container of water is a better way of watering than watering the plant from overhead as this stops the soil capping and/or leaf scorch if watering on a sunny day.
- A tomato fertiliser that’s high in potash is ideal to encourage more flowers rather than a fertiliser that’s high in nitrogen that encourages more foliage.
- Remove spent flowers and seedpods because sweet peas won’t produce new buds whilst there are still old flowers and seedpods on the plant.
Sweet peas are an incredibly rewarding plant to grow in any garden style or size. With fantastic flowers and fragrance, they have so much to offer. So, when there are problems, there’s always a solution to continue to grow the best sweet peas.
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Frequently Asked Questions:
1. Why are my sweet pea flowers dropping suddenly?
Sudden flower drop in sweet peas is typically due to stress from temperature swings or inconsistent watering—not pests. Improve flower retention by planting once night temperatures stabilise, using lukewarm water, and maintaining evenly moist, mulched soil.
2. What’s the best way to keep slugs and snails off sweet peas?
Rather than relying on pellets, use a mix of tactics: plant strong-smelling herbs nearby, encourage wildlife like frogs or hedgehogs, and consider laying sacrificial plants such as nasturtiums to lure pests away from your sweet peas.
3 – How should I water sweet peas to avoid common issues?
Aim for early morning watering using tepid water to avoid shocking the roots. Avoid wetting the leaves and instead water at soil level or stand containers in trays to soak up from the bottom—helping avoid mildew and leaf scorch.
4 – What’s the best fertiliser to boost sweet pea flowers?
To keep blooms coming, use a flower-focused feed high in potassium, like a tomato fertiliser. Avoid nitrogen-heavy formulas as they encourage leafy growth at the expense of flowers, especially in already rich soil.
5 – Can sweet peas grow well in containers or small spaces?
Definitely. With their climbing nature, sweet peas excel in containers when given sturdy vertical supports like wigwams or obelisks. A deep pot, consistent watering, and good drainage are all that’s needed for success in tight spots.
David Domoney is a Chartered Horticulturalist, Broadcaster, and Author. David has worked with a number of the UK’s leading garden retailers as a plant buyer and strategic consultant. With more than 30 years experience, in horticulture, David is as passionate about plants now as he was when he bought his first plant at a village fete.
Can yellow leaves on sweet peas be corrected
we had the most amazing garden in Huntington Beach. People would stop and take pictures. Yes we had snails all day long but not in AZ. We are struggling trying to work this garden. Bell and hot peppers all day long, actually grew the most amazing perfect Walla Walla onions. We are not sure what is in our garden that is eating the sweet peas. We do not use chemicals or pesticides so we need a good resolve.