To preserve your harvest, we suggest, drying them whole to use in fall arrangements, holiday wreaths or other festive designs. If you want to preserve them for later use in a tisane (a herbal infusion), it's best to coarsely chop the large rosehips in a food processor before air drying and storing in an air tight tin. Rosehips yield a pretty pink brew, rich in Vitamin C.
To make the tisane, add about 1/2 teaspoon of the crushed hips to a cup of boiling water; steep five minutes until the color is bright pink. Add sugar, honey, or lemon if you like, and by all means try it with cloves and cinnamon-stick stirrers.
(excerpt from Bertha Reppert's A Heritage of Herbs, 1976, Stackpole Books).