Press kits are a little passe these days. They're designed to provide information for journalists (not really for the general public). But journalists won't be interested in your press kit unless you've got a really newsworthy story. Read the publications that you are trying to target to determine what kinds of stories they cover. Focus on local community newspapers to start. Magazines that cover weddings have lead times of several months to a year. You'd have a real job ahead of you trying to get a story in one of those.
If you want to do this, hire a publicist to create one for you, or research how to do it. There is a right way and a wrong way to write press releases and create press kits. The last thing you want to do is irritate your local press with self-promotional releases and press kits. They will go right in the circular file!
You can create an online press kit on your website. You'll want to include background information about your business (a backgrounder) which simply describes where you're located, how long you've been in business, number of employees, what services you provide, any awards you have won, any professional organizations to which you belong, and the name of the owner. If you have donated items or provided volunteer hours to the charity (not you, personally, but your business), you can also include that.
High resolution photographs are often in demand. But ask before you send them. You can include them on your website or Flickr page.
Again, you would only issue a press release for something really newsworthy and different. Can you think of wedding articles that just haven't been covered before? What are the trends in wedding floral design? If you're going for feature articles or human interest stories, try sending those in July and August when news is slow.
There are loads of ways you can promote a wedding floral business more effectively. Think creative partnerships, and opt-in e-mail, or even a blog! If you become involved with your local business community and chamber of commerce, you'll probably pick up lots of tips, too. Good luck.