A souvenir or wild potpourri need not be complex or even scented. A wild potpourri needs only be created from items gathered from gardens - petals, leaves, buds and twigs or things you've found in Nature.
Glean from safe wild plants, such as seeds, pods, berries (if in doubt, leave it out), and feathers found under trees.
Desert areas, mountains, and seashore will yield up stones, pine cones, and shells.
If you want scent add a few drops of essential oil, some lavender buds, or scented flower petals or aromatic herbs.
Place your collection in a pretty dish and set it somewhere that you can enjoy it.
Not only will you have something beautiful to commemorate a vacation, an Autumn walk, or visit with a friend or family member, you'll have a lovely and frugal souvenir that you can enjoy for a long time to come.