If your intent is to present your host with a lovely bouquet of flowers to be placed anywhere in the home, then there is no need to have it delivered in advance. Take it with you as you would if you were taking a bottle of wine. You’ll have the priceless opportunity to witness the joy in your host’s eyes when presented with such a refreshing gift and the discomfort of feeling empty-handed will be eliminated. Having these flowers in a vase is preferred over a bouquet without a vase. Your host has too many things to worry about and having to find a vase to fit your bouquet will only add to their stress. Make it simple and easy by taking a vase arrangement with you.
For a host who is very particular, you may want to discuss the colors with them prior to purchasing the centerpiece. Don’t take the flower centerpieces yourself, have your local florist deliver them in advance. This will give your host the time to arrange them based on how they will fit in with their table setup and you can rest assure they will be delivered intact.