What flowers can I grow for an early June wedding?

Welcome to the Vine Joannem.
Sorry if this disappoints you but given that this is the 10th May I can't think of anything you could grow that would be ready for table centres and bouquets in early June. It all takes a bit longer than that.
But maybe there's some genius on here who can come up with something.

Hi and welcome Joannem. Good luck for your wedding in June 2011 however I can only help a little. Depends what flowers you're looking for.... My peonys are just coming into fantastic bloom and as I'm further south than you, should be about right. Perhaps some scented sweetpeas? you can play with the timing next year.....

Sweet peas may be ready some Roses would be in flower, Lily's but you would need to be careful of the pollen but you could nip that bit out. If I think of anything else will come back.

Hi Joannem, why not have a look around some garden centres during June to see what is flowing well, what you like, and what might suit your themes etc. You can then ask advice ragarding the growing of the flowers that you like from the garden centre staff.
Things like OSTEOSPERMUM might suit?

Firstly CONGRATULATIONS! I wish I had 2 years to plan my wedding!

Lillies I think would be lovely for your bouquets - quite popular as a wedding flower and quite easy to grow (I think). You just buy the bulbs in a wide range of stores Tesco; Homebase; B&Q; Poundland; garden centres; flower markets... You get around 3-5 bulbs per pack for a few quid (or £1 in poundland ). One bulb = one plant, and you get a few blooms off each plant. For scented lillies, choose the orientals (like stargazer) - they have large blooms too. Asiatics are slightly smaller flowers but aren't scented. Either way, I would pick out the pollen holding stamens when using them in bouquets - they stain clothes.
Late flowering tulips make an easy and informal hand-tied bouquet. Check varieties to see what month they will flower.
You can buy rose bushes to plant now and they will flower - although you may not get enough blooms for your bouquets and button-holes. May be hard to guarantee having enough blooms at the right stage of flowering too.

Perhaps plant pots of flowers would be nice for table decorations, something like busy lizzies (impatiens) - you can grow those from seed early in the year and they should flower in the summer. Start them off indoors and they will grow quickly. (Or cheat and buy plug plants from garden centre few quid for a tray of 6 plants or so.) Nasturtiums are extremely easy to grow - can put these in pot too. One pea-sized seed = one plant with many blooms - don't choose the trailing variety if putting in pots for table though. Pansies, violas, petunias are all summer bedding plants that you can pot up into plant pots as your table decs - put pot in a ceramic pot. Ikea have a range that won't break the bank.

Just been to their site - gerberas are cheerful - might look good on your tables...
IKEA | GERBERA | Potted plant

Some cheap pots here...28p, 9cm tall, 10cm diameter
IKEA | Pots & plants | Pots | BILLIG | Plant pot

same dimensions, 9cm tall, 10cm diameter but 99p
IKEA | Pots & plants | Plants | KARDEMUMMA | Plant pot

you could use phaleanopsis orchids as your table decs...£5.86
IKEA | Pots & plants | Plants | PHALAENOPSIS | Potted plant

...hope that gives you a few ideas

Sweet Williams, foxgloves and cornflowers will be flowering in June. Any good?

Wallflowers, especially the perennial sort, they keep flowering for most of the year

Miniature sunflowers? You can time them next year, to get them about right. Sunflowers can be started indoors early to get earlier flowers, and the mini ones tend to brach out and produce more flowers.

The Cutting Garden: Growing and Arranging Garden Flowers: Amazon.co.uk: Sarah Raven, Pia Tryde: Books
This is a brilliant book about cut flowers that might help you

Sorry Joannem, I missed that the wedding was 2011.
Roses are pretty good and dependable for June.

I really like the idea of growing my own flowers for my bouquet next year - I love peach roses - anyone recommend a nice one?

You'd probably want to buy a rose a few years old, and probably more than one, to have enough for a bouquet.

eg. My Iceberg really got going this year and gave me loads, but it's 4 y.o.

What about something suitable for an Allotmenteer?
Unique, Edible Wedding Bouquet, Boutineers, and Arrangements Ideas with Vegetables for Food Lovers | Melody Fury Food Writer and Photographer

Ooo they're lovely!