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Why are my sweet peas turning yellow?

There arent many better flower displays than a wall of sweet peas in full, glorious bloom. But what if your sweet peas are a little more yellow than glorious? What causes this and what can you do about sweet peas turning yellow, lets’s have a look!


If sweet peas are sat in very damp soil all of the time then they can suffer from a problem called root rot. This is just as the name would suggest, the roots begin to rot from all the moisture. This will cause the ends of the leaves to turn yellow and start to curl.

Sweet peas do like fairly moist soil so to have this issue they have to be really overwatered. This can happen in pots that don’t have proper draining and leave the roots of the plant sitting in water.

Root rot causes the same issues as damaging the roots by transplanting and the solution is the same. The plant just needs time to recover and obviously less water. This is obviously easier to control if they are in a pot, if your sweet peas are in the ground then it may be a job for the following season to improve the drainage in that area.

Mixed colours of sweet pea flowers
Mixed colours of sweet pea flowers

Transplanting / Root Damage

All pea plants including sweet peas do not like to be moved or have their roots disturbed. If you have just moved your sweet peas or potted them onto a bigger pot then this could well be the reason the leaves are turning yellow.

If this is the case then simply leaving the plants to recover will be enough to see the yellowing reversed. If you have severely damaged the roots while transplanting then it may take a couple of weeks for them to find their feet again.


sweet peas, (Lathyrus odoratus) are a flowering plant belonging to the legume family. They are an annual flower that loves to climb and spread, in the right conditions and with the correct support they can grow to 2 and a half meters tall!

Unlike many other legumes which are grown to be eaten, sweet peas are grown for purely aesthetic reasons. There is evidence to suggest that the pea seeds from a sweet pea plant are actually toxic to humans and not fit for consumption even if this was desired.

Sweetpea FAQ’s

Are sweet peas perennial?

No sweet peas are an annual plant, they will not come back year after year.

Can you eat sweetpeas?

No, sweet peas are grown purely for their looks. Unlike many other legumes, they are actually toxic to humans if consumed.

Are sweet peas poisonous to pets?

Yes, as they are poisonous to humans they are also poisonous to pets, so make sure you keep an eye on your pets when they are hovering around sweet peas.

How high can sweet peas grow?

With the proper support, sweet peas can grow to 2m or even slightly above!

When do you grow sweet peas?

The traditional season for sweet peas is June and July but with the right care and attention, they can be both started earlier and grown later into the season. Regular deadheading of sweetpeas can massively prolong their flowering period.

How to germinate sweet peas?

I like to soak my sweet pea seeds in water for 24 hours before planting them in a seed tray. This soaking helps to break down the tough shell around the seed allowing them to germinate better.