Here is a list of safe flowers.  Remember that while some flowers are edible, it is best to just use them as decorations.  Make sure they are pesticide free before using.

Apple Blossom, Malus spp.
Begonia, (most tuberous), Begonia X tuberhybrida
Borage, Borago officinalis (must remove hairy sepals from center)
Cornflower, Centaurea cyanus
Daisy (English), Bellis perennis
Freesia, Fuchsia X hybrida
Geranium, Pelargonuim spp.
Hibiscus
Honeysuckle, Lonicera japonica
Impatiens, Impatiens wallerana
Johnny-Jump-Up, Viola tricolor
Lavender, Lavandula angustifola
Pansy, Viola X Wittrockiana
Rose, Rosa spp.
Tulips, Tulipa spp.
Violet, Viola odorata

Some Toxic Flowers and Plants:

Amaryllis, Hippeastrum puniceum
Anenome, Anemone spp.
Autumn or Meadow Crocus, Colchicum autumnale
Azalea, Rhododendrun spp.
Belladonna lily, Amaryllis spp.
Bird of Paradise, Strelitzia reginae
Bleeding Heart, Dicentra spectabilis
Buttercup, Ranunculus spp.
Caladium, Caladuim bicolor
Calla Lily, Caladuim bicolor
Cardinal Flower, Lobelia spp.
Clematis, Clematis spp.
Crocus, Dutch, Crocus vernus.
Daffodil, Narcissus spp.
Datura, Datura spp.
Delphinium, Delphinium spp.
Foxglove, Digitalis purpurea
Glorious lily, Glorious spp.
Hydrangea, Hydrangea macrophylla
Iris, Iris spp.
Jessamine, Gelsemium spervirens
Lantana, Lantana spp.
Larkspur, Delphinium ajacis
Lily-of-the-Valley, Convallaria majalis
Lupine, Lupinus spp.
Monkshood, Aconitum spp.
Narcissus, Narcissus spp.
Oleander, Nerium oleander
Periwinkle, Vinca spp.
Poinsettia, Euphorbia (Poinsettia) pulcherrima
Rhododendron, Rhododendron spp.
Star of Bethlehem, Orinthogalum spp.
Sweet Pea, Lathyrus odoratus
Wisteria, Wisteria spp.