Sadly, it isn't always as easy to tell if the flowers you buy are as fresh as your milk. Flowers don't come with a "best consumed before" date stamped on them, so there really isn't a way to know how fresh they really are or just how long they will last once you actually get them home.
The flowers that you find at the florist shop an in the aisles of your local grocery store have already been through quite a bit by the time they reach you. Flower growers spend their day selling many of their beautiful blooms directly to consumers, but at the end of the day they often find they have quite a bit of stock left over. These flowers are bundled up and shipped off to auctions and wholesalers throughout the United States and Canada, where they are sold at a discount, because they are no longer fresh. From the wholesale warehouses and actions the flowers are shipped to florists who stock them in their coolers in hopes of selling them to their customers in various arrangements. That means that when you get a bouquet of flowers delivered to you from your local florist, it might already be anywhere from 3 to 5 days old and the chances of it lasting very long are slim.
The most exquisite bouquets come from using only the freshest of flowers. To achieve freshness when you purchase flowers, cut out the middleman. Don't buy from companies that buy flowers from the grower rather, buy from the grower himself. That means that you will always get fresh cut blooms. Growers don't have to keep a consumer ready inventory of flowers on hand waiting to be placed into pretty arrangements, so they cut their flowers fresh everyday. When you buy blossoms direct from the source, they won't bloom into their full glory prematurely, giving you many more days of pleasure.