Image by: wintersown
These pods look like stringbeans. The method for saving sweet peas can be used for both annual and perennial sweet peas.
Sweet peas are a lovely old-fashioned vine, usually with flowers in the pink, mauve, and white range. Peas are in the legume family and the maturing pods will resemble stringbeans.
Allow the flowers to fade and drop naturally, where the flowers were held on the vine will develop an elongating pod that will be at first a beautiful bright medium-green, then as the pod matures and swells with seeds the bright green will begin to dull and fade to yellowy-green. When the seeds inside are fully mature the pods will turn "lunch-bag" brown. They may then be removed from the plant and placed on a plate to dry for several days.
You may notice the pods begin to split as they dry, you can help the pod to open by running the top edge of a fingernail along the seam in the pod, thus spreading it open. With your finger carefully push the seeds out of the pod and allow them to continue to dry for several more days on an open plate. Dried seeds are round and about an 1/8 inch wide, they are a dull tannish-grey.