Contrary to popular opinion, you should not cover the tender new shoots with mulch to protect them from an upcoming cold night. This will actually encourage more growth because it insulates them. The new growth can endure quite cold temperatures with no damage. It's easy to do. Select branches from your favorite flowering shrubs or trees that have good flower buds.
Flower buds are usually plumper than leaf buds and on the terminal ends of branches.
Bring the branches in and put in a container of fresh water. To speed up the process, wrap the container and branches in plastic and keep sealed to create high humidity. After you notice the buds starting to open, remove the plastic and keep the branches in water and good light. You should have a beautiful display in no time. Some of the best plants to use are Forsythia, Magnolia, Crabapple, Pear, Quince and Willow.