Lilacs are beautiful, boutiful, and fragrant May flowers. This is something long terms, though. Perhaps some friends or neighbors would be willing to share the flowers from their established bushes. They come in various shades of lilac (of course) but also white, pink and some yellow.
I will defer to other members in zone 6 &7 to advise you of
May blooming wedding flowers in your locale. Up here in northeast Connecticut, things are just getting started in May, except for bulbs that were planted the prior Fall and other perennials such as Dogwood and Magnolia.
May is a wonderful month to be married... Best wishes.
Regards, Susan

This sounds like a great idea, and I hope you can find a way to work.

I don't want to be a nay-sayer, but one big challenge is that many Spring flowers bloom at really different times, depending on what the weather is like on any given year. For instance, I had all sorts of recipe plans for violets this past year, but they bloomed a full month earlier than usual, and I was taken off-guard.

That being said, some bearded irises might bloom at the right time for you.

Thank you for your responses! Honestly, nothing has been set in stone, and if June has a bit more "Bloom" then we may just do it then. I'm just a little wary of a hot and steamy july or august wedding, Late September seems it might be ideal but you know, we just dont want to wait almost 2 years. We've already pushed it back from Oct of this year (2011) due to way too many family weddings then.

It really depends on your location, beyond the zone. The coastal areas, certainly Cape Cod, are weeks later than inland areas. You can add your general locale to your login just by putting it in the area where you normally put your zone.

Bulbs are pretty reliable - you might consider planting loads of them next fall; you'd have a pretty good idea about the timing the following spring.

May is kind of a lull in my garden, and then early June is an explosion of Irises, Digitalis, Peonies, Baptisia, etc. Although this past Spring was so warm, that the Peonies and Baptisia were in full bloom the last week of May. So it is a bit unpredictable!

The Columbine blooms in May, and it makes a beautiful cut flower. They are super easy to start from seed and will bloom the 2nd year, but you could also buy a few smaller plants this Spring which should be blooming abundantly next year.

I agree with others that bulbs, either forced or in the ground, would be the most reliable spring flower on such short notice. It took me years to get my perennial beds established and our soil was rich and fertile from years of animals pasturing on it.

Daffodils are the safest bet where I live, as they are the only bulb that does not get eaten by underground rodents. I've had beautiful crops of tulips and crocus one year, only to have them disappear the next. Only the daffies have been reliable over time. Of course if you forced bulbs, this wouldn't be a problem.

My personal favorites with a wildflower feel about them are daisies, rudbeckia and echinacia, but these all bloom at different times (at least the varieties I've grown.) Also they bloom considerably later than May here in zone 4; not sure about zones 6 and 7 though.

Best of luck with the wedding plans and I hope we get to see photos!

Congrats! May you have a beautiful wedding and a long and Happy Marriage.

I am not a big fan of trying to grow plants for a specific one day occasion. I grow plants for a plat sale that runs a MONTH and it's very hard to get the plants to be ready for the MONTH of May..never mind one DAY in May or June.

It makes me admire MA nature even more and how she pulls it all off LOL.

I linked a thread that came up a while back. It's the same question yoiu have and has some very good replies.I suggest for less expensive and guaranteed flowers you look at Costco.com.

Here is a link that might be useful: Some more thinkgs on starting flowers for a wedding.