There's not a whole lot one can do to fool Mother Nature. Begin early to encourage healthy growth & bloom production with timely fertilization & prompt attention to dead-heading chores. Then pray (perhaps to St Valentine, and certainly to Our Lady and to St Nicholas of Myra -- who, in addition to being Santa Claus is also the patron saint of brides). Ask for weeks of sunny, cloudless days prior to (and on) the big day, & pledge to celebrate the event with gusto regardless of whether Mother Nature chooses to cooperate.

I was told it takes seven weeks(could be eight but maybe this can be foud out for sure on the net) after pruning stems for a rose bush to be full of blooms once more. I know of someone who tried this in New Zealand for their daughter's wedding ceromony. Theoretically, it should work, but maybe a more accurate pruning time on the net. Good luck.
Pauline

Here on Vashon Island I have had my major bloom in early June most years. By late July they would just be beginning their second round. and early August would see them at their best. I think I would debud about half the roses from their first round in June and hope hope hope that they do well by late July and that we have a good rose summer!

You need specific information from rose exhibitors in your neighborhood as to how they time their blooms for a show.

I've done roses for three nieces' weddings and fall is easier to plan.
Don't rely on one kind of rose; don't rely on one massive rose bush (Eden, which I planned to use for the bridal bouquet got the worst case of thrips in creation and brown edged roses don't do it. That bouquet ended up being noisettes and polyanthas)
If you hear hot weather predicted, the roses will come faster, maybe as much as two weeks faster than normal.
Line up refrigerators to hold buds and blooms that come to early. Test those refrigerators with max/min thermometers to find ones that the bud area doesn't get below 26F.

Have rose friends nearby you can depend on.
Have alternative flowers growing.
Have a source for commercial roses as a back up.

Consider using the cute blooming minis from Canada as Brides Maids bouquets.

Let there be lots of alternatives and don't stress the small stuff....it's all small stuff....the wedding itself is the big stuff.

You would have to adjust for your zone and the timing, but the folks at the Santa Clarita Valley Rose Society have a few articles on the subject (pruning for rose show timing) that might help.

How to have Beautiful Roses for Bloom in October

Understanding the Bloom Cycles of Roses

You would probably lose your June blooms since you would have to prune in late May/early June. And, all bets are off if the weather isn't perfect. Too hot or too cool or Nor'Easter/hurricane (or whatever similar kind of storm you get in your part of the country) and that's that. Heed what Ann writes, really.

Seems to me that the most important question regards what you're actually hoping for. Do you want blossoms to cut for bouquets and table and/or altar arrangements, or are you hoping for bushes that are in full bloom to enhance the setting for a garden wedding?

I usually have a first bloom mid June too so you might want to cut them back about 7 weeks before the wedding even if they haven't bloomed completely.
I'd also give them a good dose of high nitrogen fertilizer and keep them well watered.
Hopefully our early Summer will give us lots of sun so your blooms will co-operate.
Good luck

With a pruning time around April 15th you should be able to have a good number of blooms for the wedding.