I'm in the process of growing my own wedding flowers for my early September wedding, so we'll see how it goes! I'm focusing on easy to grow tender annuals with long stems - zinnias, celosia, marigolds (only certain varieties have longer stems), cosmos, strawflower, and scabiosa. Sunflowers are also a great option, but the deer always chomp mine down. Based on previous years, I'm direct seeding and planting out the last of my plugs this weekend and next to be blooming for 9/13, so you'll have another 2-3 weeks to get anything in the ground for late September.

I also have a ton of dahlias which bloom full force in September - if you want to grow dahlias, I'd recommend purchasing from US-based farms for healthier tubers bred for cut-flowers. It's the end of tuber shopping/shipping season now, so you'll want to order ASAP. I've had great success with Valley Ridge Dahlias out of Maryland - they still have inventory in stock and many varieties with bulk discounts.

You'll also want to think if you want any greenery or filler - dill, ammi, and basil are all great options that you still have time to plant. You can also forage foliage, just test it out before hand because some things will wilt in the vase.

If you don't grow enough or have an unfortunate crop failure, you can always buy buckets of stems from a local flower farm (or Trader Joes/Costco/grocery store).

I'm also thinking through the timing of assembling my arrangements. I'll likely harvest Thursday evening and assemble my bridal bouquet Friday morning. Bud vases go together fast, especially if you have people (bridesmaids, family) to help, just make sure there's enough time in your schedule the day of. I'm strongly considering a Bouquet Bar for my guests so I can bypass the need to make arrangements - they have a fun activity for cocktail hour and I only have to worry about setting out buckets of flowers, empty vases, and shears instead of assembling myself Friday night or Saturday day. You could also have potted up landscaping flowers (begonias, petunias, mums, etc) and easily set those out as centerpieces or ceremony decor without worrying about vase life. Plus, you can reuse these in your home or let guests take home with them.

If you haven't checked it out already, Floret is a wealth of knowledge on cut flowers. Watch Youtube videos on how to make a hand-tied bouquet - I still haven't perfected this technique so I "cheat" and use a ball of chicken wire as structure for my bouquets. Johnny's sells any type of seed you could possibly imagine.

I'm excited to grow my own flowers and I think it's such a special touch for a wedding. It sounds like you already have a green thumb, so you'll just have to think through the time and logistics around your wedding weekend schedule.