I've created a list of the flowers that should be available each season for those wanting to know what flowers will be available for their wedding date. It's always recommended to choose a colour palette and base your florals around this to avoid disappointment when outside forces impact what flowers are actually available to us.
SUMMER
December, January, February
Achillea
Agapanthus
Ageratum
Alstroemeria
Amaranthus
Anthurium
Aster
Bells of Ireland (Molucca Balm)
Bird of Paradise (Strelitzia)
Bouvardia
Calla Lily
Carnation
Celosia
Chrysanthemum
Copper Beech Foliage
Cornflower
Cosmos
Cow Udder
Crab Apple Branches
Dahlia
Daisy
Dancing Lady Orchid
David Austin Rose
Delphinium
Echinacea
Feverfew (Mayflower, Matricaria)
Flowering Gum
Gerbera
Gardenia Flower
Gladioli
Globe Thistle (Echinops; February)
Gloriosa Lily
Gomphrena (Bachelor's Button; Globe Amaranth)
Gymea Lily
Heliconia
Hydrangea
Hypericum Berry
Iris
Kangaroo Paw
King Protea
Larkspur
Lavender
Liatris
Lily
Lisianthus
Lotus Flower
Marigold
Moss
Peony (5 weeks from November to early December)
Phalaenopsis Orchid
Protea (February, March)
Queen Anne’s Lace (January)
Rose
Rudbeckia
Scabiosa
Scabiosa Pod
Sea Holly (Eryngium)
Singapore Orchid
Snapdragon
Statice
Stephanotis
Stock
Sunflower
Veronica
Water Lily
Xerochrysum Bracteatum (Everlasting Daisy)
Zinnia
AUTUMN
March, April, May
Alstroemeria
Aster
Anthurium
Amaranthus
Billy Button
Bird of Paradise (Strelitzia)
Bouvardia
Calla Lily
Camellia Flower
Celosia
Chrysanthemum
Cornflower
Cosmos
Cymbidium Orchid
Dahlia
Daphne
David Austin Rose
Delphinium
Disbud
Double Tulip
Earlicheer
Easter Daisy
Freesia
Gerbera
Gladioli
Gloriosa Lily
Gomphrena (Bachelor's Button; Globe Amaranth)
Hyacinth
Hydrangea
Iris
King Protea
Lavender
Lily
Lisianthus
Moss
Nerine
Ornamental Kale
Parrot Tulip
Peony (imported; around May)
Phalaenopsis Orchid
Poppy (starting May)
Protea
Queen Anne’s Lace
Rose
Sedum
Singapore Orchid
Snapdragon
Solidaster
Statice
Stock (late Autumn)
Thryptomene
Tuberose
Tulip
Violet (late Autumn)
Xerochrysum Bracteatum (Everlasting Daisy)
WINTER
June, July, August
Alstroemeria
Anemone (approx., July to October)
Anthurium
Arum Lily
Astilbe
Banksia
Billy Button
Bird of Paradise (Strelitzia)
Blossom
Blushing Bride
Calla Lily
Calendula
Chrysanthemum
Cymbidium Orchid
Daffodil
Daisy
Daphne
Delphinium
Disbud
Double tulip
Earlicheer
Flannel Flower
Flowering Viburnum
Freesia
Gladioli
Grevillea
Hellebore
Hyacinth
Iris
Jasmine Buds/Flower
Jonquil
Kale
Kangaroo Paw
King Protea (June/August white)
Lavender
Leucadendron
Leucospermum cordifolium (July, August)
Lily
Lisianthus (imported)
Mulla Mulla (June)
Ornamental Kale
Parrot Tulip
Peony (imported)
Phylica (Featherbush)
Poppy (late Autumn approx., May)
Protea
Phalaenopsis Orchid
Ranunculus (late Winter)
Red Hot Poker
Rose
Sea Holly (Eryngium)
Snapdragon
Star of Bethlehem (Arab's Eye)
Stock
Sunflower
Sweet Pea
Thryptomene
Tulip
Waratah
Wattle
Waxflower (September, October)
Xerochrysum Bracteatum (Everlasting Daisy)
SPRING
September, October, November
Allium
Alstroemeria
Anemone (approx., July to October)
Anthurium
Arum Lily
Bearded Iris
Bells of Ireland (Molucca Balm)
Bluebells
Blushing Bride
Boronia
Calla Lily
Canterbury Bells
Carnation
Chincherinchee
Chrysanthemum,
Cornflower (October, November)
Cymbidium Orchid
Daffodil
Daisy
David Austin Roses (approx., late September)
Delphinium
Dogwood (ate spring)
Easter Daisy
Erica
Flannel Flower
Freesia
Gardenia Flower
Gerbera
Gladioli
Grevillea
Hellebore
Hippeastrum
Hyacinth
Jasmine
Jonquil
Kangaroo Paw
King Protea
Larkspur
Lavender
Leucadendron
Leucospermum cordifolium
Lilac (3-4 weeks approx., September/October)
Lily
Lily of the Valley (approx., 3 weeks in September)
Lisianthus
Nigella
Paniculata
Peony (5 weeks from November to early December)
Phalaenopsis Orchid
Phlox
Pieris
Pin Cushion
Poppy (approx., May to early October)
Protea
Queen Anne’s Lace
Ranunculus
Rhodanthe (Paper Daisy)
Rhododendron
Rice flower
Rose
Scabiosa
Smokebush
Snapdragon
Snowball Viburnum
Statice
Stock
Sweet pea
Tree Peony
Tulip
Tuberose
Tweedia
Waratah
Water Lily
Waxflower (September, October)
Xerochrysum Bracteatum (Everlasting Daisy)