Just over the border from us, the town of Wem hosts an annual Sweet Pea Festival and Show. A local resident, Henry Eckford became internationally famous for his work in breeding and developing new sweet pea varieties. Several varieties are named for him and his family, one of my favourites is lathyrus odoratus Dorothy Eckford, named after his daughter.
I prefer the old fashioned, heavily scented heirloom varieties; 'Cupani' said to be the first sweet pea introduced from native Sicily. Other favourites are 'Matucana' - two tone dark pink and purple and 'Erewhon' in delicate shades of pale blue and mauve. My Mum loved sweet peas but found the heady scent made her sneeze. So she grew the Spencer and modern Grandiflora types with larger flowers but usually less scent. Our most popular packet is a mixture 'Heaven Scent' with a range of colours, highly scented. Different types for everyone - take your pick, so many to choose from.
I will cut the last few stems of my sweet peas before winter storms hit. As they come to an end after a glorious season of heady scented blooms, I am starting next year's planting. I sow my sweet peas in root-trainers, one or two to a module depending on the variety. You could use pots, sowing three or four in 3" (8cm) pot. Keep in a sheltered location outside, watch out for slugs and mice! When about 6" (15cm) tall, I pinch out the plants (nip off the growing tips of the stems) to encourage the plants to bush out. You can sow direct at the base of their growing support in the spring too, about 6" (15cm) apart.
When planting out in the spring I will have added organic matter (home compost from my hot-bin) at the site to improve moisture retention at their roots as sweet peas prefer their heads in the sun. They need support such as a trellis or frame. I use an obelisk with extra strings for the vines to scramble up.
Water the roots during dry spells, then your only task is to keep cutting the flowers. These peas are NOT edible so keep removing dead flowers before any pods form. The more you pick the flowers, the more they will bloom.