For every wedding, the bride is usually the person who would want specifics. It is not really unusual, since men are often taking care of the general outcome (that is why there are more men who are general managers), and women take care of the details (that is why women are better off at taking care of the nitty gritty stuff, hence, women are good at crafting too). Since weddings come, often once in a lifetime, the women would want it one of the most special events in their lives.
Even if the bride-to-be is not creative, most would have an idea what they like. She can start by looking over at the wedding decorations that already exist. From there, ideas will emerge. The person in charge of the idea can mix and match accordingly and relay it to the person who will actually take care of getting everything done within the specified time frame. Even if you are a true blood crafter, having to do everything yourself will drain you down and will cause you to be tired and haggard come wedding day. Learn to delegate and have the precious time spent on relationship building instead. If weddings happen once in a lifetime, the bride ought to be the most beautiful she can be.