Q.Yellowing Leaves on Sweet Peas and Margarette Standard
Hi
Despite very regular care (i.e. dead heading and picking) my Margarette standard foliage went yellow and the flowers got smaller and scarcer to the point I have now cut it all back. Also, the leaves on my Sweet Peas are also yellowing although they are continuing to flower pretty well.
Could you advise what’s causing it please.
Thank you
Lynne

Yellowing leaves can indicate watering issues, disease, pests or nutrient issues.
Inspect the plants and leaves for signs of insects or markings.
Check the soil. Is it well draining? Lack of water or excess moisture can be an issue.
These articles will refresh you on the care requirements.
https://www.gardeningknowhow.com/ornamental/flowers/sweet-pea/care-of-sweet-peas.htm
https://www.gardeningknowhow.com/ornamental/flowers/sweet-pea/sweet-pea-flowers-falling-off.htm
https://www.gardeningknowhow.com/ornamental/flowers/marguerite-daisies/marguerite-daisy-flowers.htm