Here are a few things to remember when you're cutting branches of trees and shrubs to force into indoor bloom:
Choose trees and shrubs that bloom in early spring, such as forsythia, flowering quince, crabapple, plums and cherries.
Cut branches about six weeks ahead of their natural bloom time. When flower buds begin to swell, it's usually the right time to start forcing them.
Avoid cutting branches early in the morning. Cut them at the warmest time of day (usually early afternoon) to ensure there is sap in the branches.
Look for branches with the biggest buds, and cut those. But keep in mind that you're also pruning the tree or shrub—consider what effect each cut will have on the plant's shape, before you make it. Try to cut symmetrically.
Soak the branches overnight in warm water. The entire branch should be under water; the point is to soften the buds and make them easier to open. It may be easiest to lay them in the bathtub and cover them with water. The next morning, cut an inch off the bottom of the branches and arrange them in a vase of water.
The very best place to put the vase while you await the bloom is a bright, sunny spot in a cool (55˚–65˚F) room.
Always keep water in the vase. You can move the branches to other rooms once they start to bloom, but cool temperatures will prolong the show.