Sweetpeas
One of my must have flowers in the garden.
Picking the flowers regularly is important to prevent the plants setting seeds and ensure continued flowering. The summer heat will put an end to the life of the vines. Let them die back and collect any seedpods once they are brown and before they split to expel the seeds. Put them in a container for planting the next year. I let the seeds fall to the ground and they come back year after year.
Sweetpea seeds will be true to the parent as they self pollinate.
Most sweetpeas require a trellis - Jack's gutter guard roll from Bunnings is cheap and easy solution. Just nail it to your paling fence.
Short lived vase flowers 4-5 days but the fragrance colour variations and shape of vine folliage with tendrils make them a favourite in a flower arrangement.