Perennial sweet peas are rambling plants that are ideal for growing over a hedge, through other plants or up into a tree. They produce delicate blooms of red, pink or white all summer and up until the frosts of winter kill the plant down to ground level. They will seed prolifically, so removing the seed pods is a good way to prevent spreading and it also makes sure the plant continues to flower.
Paper bag, Paper envelopes, Airtight container, Pen
To save seed for future use or sharing with friends, collect the seed heads as the pods begin to turn brown. Either lay them on paper in a seed tray or put them into a paper bag. Seed release can be explosive, so the bag will make sure none are lost.
Put the bag somewhere dry and away from the sun until the seeds are all released. This should take a few days.
Separate out any pale, unripe seeds. These are not dry enough to put into storage with the rest. You can ripen them in a saucer on a sunny windowsill if the seed numbers are low, but otherwise discard them.
Store in paper envelopes in an airtight container and place this in a cool, dark, frost-free spot until you are ready to use them. Clearly label the pack with the name of the seed and the date they were collected.
Growing a Lily in a Container