All you need is a sharp knife or pruning shears, several containers, water and a floral preserving solution and of course, some prunings off spring flowering shrubs or trees. Shrubs are generally easier to bring into bloom than trees, although I've had success with cuttings from a star magnolia. Here's what to do:
On a day that is not bitterly cold, go out to your garden and decide where you would prune to get a more natural or formal shape, depending on your tastes. Shrubs that are relatively easy to force include:
Forsythia (Forsythia, various hybrids)
Bridal wreath spirea (Spirea x vanhouttii)
Deutzia (Deutzia scabra, D. gracilis (photo, below)
Mock orange (Philadelphus x virginalis)
Witch hazel (Hamamelis virginiana)
Pieris (Pieris japonica, various hybrids)
Flowering quince (Chaenomeles speciosa, C. japonica)
Flowering fruit trees (cherry, crab, etc)
Honeysuckle (Lonicera, various)
Bittersweet vine (for leaves; the flowers are insignificant)
Magnolia, especially M. stellata
Select twigs or young branches that are between 6-18 inches long, for ease of use in containers, and make a clean cut as close to the main branch as you can. Flower buds are larger and plumper than leaf buds, so you should be able to determine whether you’re cutting branches with plenty of flower buds or only a few. Make a second cut on each stem, sharply angled to allow better water uptake. If it was very cold when you collected your branches, put them in the bathtub for a few hours in tepid water, to allow them to gradually acclimatize to the temperature changes.
Next, unless you have a few packets of ready-made floral preservative kicking around, make a homemade solution. The simplest one combines 2 tablespoons of white vinegar, 2 tablespoons of sugar, and half a teaspoon of bleach in one quart of water.
Arrange your branches in an upright container such as a tall vase or jar, with a couple of inches of warm water in the bottom (about 110 degrees, the same as for proofing yeast when making bread.) Leave your twigs stand in this for about half an hour, and then fill the jar with floral preservative solution. Check daily and top up with additional solution as required. Put your containers into a cool room with minimal light (no direct light) for several weeks, until buds start to show colour. Then you can move your twigs into a brighter location, and arrange them in a decorative vase, kenzan, or other container. (above, Thunderchild crabapple)
The length of time it will take for your branches to sprout can vary from 10 days (forsythia) to5 weeks, (pieris, magnolia) depending on the time of winter and the type of plant. To keep your branches blooming for a longer period of time, move them into a cooler room at night, and don’t put them in sunny windows. (Above, Jelena Hamamelis)
Occasionally, your coaxed branches will develop small roots. If desired, you can grow these into small saplings; cut the twigs back to about 6 inches in length, and pot up in a good quality potting mixture. When spring comes, plant out in a nursery bed, where they may need to stay for several years until large enough to move into your preferred location.