Here are a few things to keep in mind:
- Flowers are ONLY edible if they were either organically grown or treated with organic pesticides like those used on fruits and vegetables.
- You must be aware of people's allergies when considering which flowers are useable.
- Do not eat flowers growing on the side of the road, because emissions from cars and chemicals used by municipalities may contaminate them.
- Flowers from florists, nurseries or garden centers are grown for decoration, and normally have been chemically treated, either by fertilizers or pesticides. They aren't safe unelss you know they've been maintained organically.
- Remove pistils and stamens from flowers before eating. Eat only the petals.
- Do not ingest large quantities of any blossom until you have first tested the effects of a single bud.
- Although a flower may be edible, it may not be palatable to some people's tastes.
- The safest method is to grow the flowers yourself, so that you KNOW what has gone into them!
Here is a list of flowers which are considered to be edible:
Alliums | Apricot petals | Apple blossoms | Bean blossoms | Begonia | Squash Blossoms | Calendula | Carnations | Chrysanthemums | Citrus blossoms | Clover | Crabapple | Dandelions | Daylilies | Dianthus | Geraniums | Ginger | Gladiolas | Hibiscus | Hollyhock | Honeysuckle | Hyacinth | Johnny-Jump-Ups | Lavendar | Lilies | Marigolds | Monarda | Nasturtiums | Pansies | Peach blossoms | Pear blossoms | Peonies | Plum blossoms | Primrose | Roses | Strawberry flowers | Tulips | Violets
Remember to always wash flowers thoroughly to make certain any chemical or organic pesticide has been removed. Happy munching!
source: lecture in my uni. class by David King, Horticultural Consultant (greenman@ucla.edu) | 
