Let's see... white agapanthus, trachelospermum jasminoides, gardenia. I'm not sure when Calla lilies bloom, they may be done before your festivities.

My callas are done by then. Here, lilies can bloom into June. Feverfew, Brugmansia, Hippeastrum, daylilies (not very white) Frequent Flyer irises, Cosmos Purity White, white larkspur. You can still plant seeds for feverfew, cosmos, and larkspur and you may get flowers. Send me a private message- I have some seeds.
Renee

You know what else might bloom then? Glads. And now is the time to plant them.
Renee

If you are talking about a year and a half from now, then I think you have many choices.. If you mean this spring, then I think annuals are your best bet.

Late may in Ncal for me, (and white) ,Watsonia, CA poppies (white strain), Shirley poppies (hard to separate the whites) Roses of course, Iceland poppies hanging in there, linaria - toadflax (hard to get separate colors), Nemesia, sweet peas hanging in there, Delphinium, Foxglove, Larkspur, Lunaria, Cyclamen hanging on,
Nicotiana, Alyssum...

I know that some seed vendors like T&M used to sell single color mixed seed packets...

Chad

I'd suggest you check out the web site for Annie's Annuals @ www.anniesannuals.com. Her nursery is in Richmond, Ca. and will have dozens of plants that would serve your purpose. You can do a search by color of bloom, and it will come up with many less common possibilities. I'm assuming this bed is full sun if you intend to plant roses, and Iceberg would be a good choice. If it isn't too hot and full all day sun, white Impatiens might be a good choice. You might also expand your list to include plants with silver foliage, which combines so nicely with white flowers. Many choices here, check out things like Sideritis cypria with silver foliage and green flowers. A border of Echeveria elegan with pale gray foliage might also be interesting. Perennials such as Centranthus rubra v. alba can be a bit weedy if let to go to seed, but will generate white flowers almost all year round and makes a great filler type of flower. Some of the smaller leaved Hebe species such as H. menziesii and H. buxifolia have showy white flowers in late spring/early summer as well, and can be kept clipped like a boxwood hedge if you like that sort of look. White variegated foliage on plants such as Tulbaghia violacea 'Silver Lace', or Carex oshimensis 'Evergold' can also give a "white" foliage effect. White flowered bedding Dahlias are also pretty reliable.

Columbine blooms in the spring. You could buy small plants now and hope they bloom in time. You could try seeds, but you may not have enough time. I did white seeds once and I got good germination rates. But, this photo was one I bought.

Here is a link that might be useful: white columbine

That time of year GBOP is in bloom..spectacular white and black flowers.

Stanofh- what is GBOP?
Renee

Strelitzia nicolai, or giant bird of paradise.

Rosefolly -Cosmos Sonata is a knee high neat cosmos that I love, I have a white bedding snapdragon (6 to 8" high), liriope with white and green variegated leaves (more common is the gold in the variegated ones, flowers are purple but they come later than your wedding date), love the airy effect of gaura lindhiermi whirling butterflies - but even by next year the plants won't be all that large - they're one plant that can look sad until it's established. Your roses won't be very big after only one season in the ground either - do plan to fill in spaces with annuals. You might get a white large flowering clematis or a white passion fruit vine (they'd both be small next year but look lovely on a support), I also love Susie White eyed the white black eyed Susan Vine. In addition to the bedding dahlias Bahia mentioned you could do a white "dinnerplate" style, and there are the "fluffy" shasta daisies like "crazy daisy" (some folks don't like the smell of shastas and feverfew - I'm ok with it). I've also had great luck with lavatera twins white (gold medal winner). Some local nurseries will order and hold things - you might just plan at the end of April next year to see how it's progressing, then order a bunch of white petunias and alyssum to fill in.

So many wonderful suggestions. Perhaps some of you have done this before?

I think this bed will be full of lovely flowers just when I want them. There will be four white HT roses and three white clematis. From Annie's I have ordered white delphinium and white foxgloves, as well as an experimental white lupin. I'm planning to add white snapdragon 'Royal Bride' as suggested by a friend. White cosmos and white impatiens are a very good idea. One end of the bed is in shade for part of the day. I have made arrangements with a local peony nursery to visit them this May and pick out peonies in bloom at that time. I will purchase then then for planting to bloom the following May, though they will not be well developed yet. Still, I can try. Some white alyssum for filler and the bed will be abundantly planted.

Thanks, everyone.