Yes, Miriam is quite right Daisy, Sweet Peas (Lathyrus odoratus) are annuals and although it is possible to grow them in Mediterranean climates their life and flowering period is curtailed once temperatures soar and the soil dries out. I started growing them several years ago as I have fond memories of picking them to put in the house. After my first attempt I was disappointed with their performance. I had sown the seeds in early spring and by the time the plants were in flower the hot weather arrived and they succumbed very quickly as I do not water. That autumn I noticed quite a few young plants had germinated from fallen seed and was pleased to see they survived the winter. These plants grew away quickly in the early spring and started to flower much earlier and therefore gave me flowers over a longer period. Now I just let nature do its job and this year, after an abnormally wet late winter and spring I have had a glorious display that has lasted for many weeks due to continuing frequent rain and lower than normal temperatures. Plants appeared in unexpected places and climbed into surrounding shrubs that gave them natural support and some of the colour combinations were quite stunning such as those of the colour in your 'photo Daisy that grew through a Rosa rubifolia.