Ahhhh...You are a good friend...but note the silence....
No one has the heart to tell you it's a sweet plan but almost impossible with out a greenhouse and some experience to force flowers to flower and bloom on schedule. Specifically this year...

My best advice? look at ordering cut flowers from a Costco. Lots of people do it for weddings , they quality is top notch and the prices are reasonable.
Good luck

Sorry but I have to agree with ontheteam .... and this is based on experience. My daughter had a small wedding in our backyard. The setting was great ... along a 60 foot perennial garden that spread out at the end into patio area which led down to a river... and the weather was perfect!

All the flowers were arranged by my daughter's new SIL... she grew up in the floral business on a family-owned nursery that supplied flowers to retailers. In fact, her main responsibility there was to create bridal bouquets and table arrangements for clients.

Early on she told us to purchase flowers as the main elements of my daughter's bouquet and the table settings.... she'd use leaves and flowers from my garden as fillers. Even though I always grow annuals among my perennials, she said there was no way to guarantee the condition of my flowers for the wedding.

I'm glad we followed her advice. Everything she created was fresh and beautiful. The "leftover" flowers went into vases that brightened up our home and also carried the wedding colors indoors.

I have to agree with ontheteam and mjc_molie. My daughter was also married on July 17. A friend with her own floral design business did the flowers and used the Boston flower mart for the showcase flowers. She uses her garden flowers for fillers and greens.

A friend who worked at a floral design shop in Back Bay would rave about the Boston flower market as the "only place I should think of buying lucky bamboo" among other things. They're a good bet.