From the ArcaMax Publishing, Wedding Guide Newsletter:
http://www.arcamax.com/news/weddings/s-26789-220777
Floral arrangements are usually a big expense as well as a focal point
of any wedding. Here are some tips to help you make choices about the
purchasing of floral arrangements for your wedding.
First, it's important to know how many people will be in your wedding
party well ahead of time. Florists need at least three to six months
to plan and prepare, depending on the size of the wedding. It is also
important to have a date set before you meet with them; the time of
year the wedding takes place will affect the cost and availability of
flowers.
In addition to knowing dates and other specifics, you should also have
your color scheme worked out. If you meet the florist with colors
already in mind, your meeting will go a lot more smoothly, and
possibly last not much more than an hour.
Also, don't plan your wedding for any time around Valentine's Day or
Mother's Day. Because of the high demand for flowers, they may cost
up to three times more than they would at any other time of year.