For a long time my foraging bible was Richard Mabey's "Food for Free". It's still a fantastic book and I still occasionally dip into it. However, last year it was usurped by "The Hedgerow Handbook" by Adele Nozedar.
In the run-up to spring I thought I'd share this with you. Primroses (and cowslips) appear in April. Freshly picked leaves and flowers can be eaten in salads or can be used as an infusion to make a tea (I've never tried that so if you do, let me know what it's like). If you do pick them please make sure you don't pull them up by the roots!
3-4 primroses (flowers and leaves)
1 egg white
Drop of rose water
1. Beat the egg white with the rose water.
2. Paint on the flowers and leaves with a paintbrush.
3. Dip in the sugar, making sure they are well covered.
4. Leave in a dry place overnight.
Use them to decorate cakes, biscuits etc.