Select healthy portions of the plants, free of insect infestation.
Cut the grasses with a pruner or sharp knife. Put the stems in water as you are cutting more stems.
Cut more plants than you want, in case any portions should become damaged.
Wash any cones or pods with water and mild detergent, as needed.
Tie the plants in small bundles at the stem ends and hang upside-down in a warm, dark, dry place.
Spray hairspray, spray lacquer or shellac onto parts such as cattails or fragile seed heads once the plants have dried, to maintain their appearance and prevent breakage.
Store dried grasses in boxes or airtight containers until you are ready to use them (airtight containers offer protection against rodents and insects).