1. Chill them...until the last possible minute
2. Copy them. Two is better than one, so why not have one bouquet for the ceremony and then a fresh one for pictures.
3. Plant them. Use potted plants as arrangements. It is trendy, different and cost effective because you can also give them away as favors at the end of the evening. (Less clean up too!)
4. Fake them. If you want flowers in your hair...why not make it the kind you can hairspray?
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If you want to take your chances with a bouquet sans "stunt double", flowers in your hair or as decor during the summer months, you should choose ones that can stand the heat... like these:
Astilbe
Cosmos
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Garden Roses - most colors and oh so delicious smelling!
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Hydrangea
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Lady's Mantle
Mint - we just LOVE that soothing smell!
Orchids - most heat resistant
Wake up and smell the roses...it's SUMMER! :)