Azaleas are commonly used in both traditional and modern bonsai. Azaleas are relatively small flowering bushes in the rhododendron family. The Satsuki azalea is often used for bonsai because of both its hardiness and its showy flowers. Azaleas bloom in late spring and can have either white, pink, purple, or one of a number of other colors. Preparing a young azalea for cultivation as a bonsai is not difficult. With the right tools and several years, you can train a very plain azalea into a highly structured bonsai.
Decide on the overall style you want for your azalea bonsai. Common overall styles include formal upright, informal upright, slanting, cascade and semi-cascade. Any one of the forms will work well with an azalea.
Remove the azalea from its nursery pot. In some cases, you may need to use a hand shovel to loosen any roots that adhere to the sides of the pot.
Shake off the soil from around the roots, and comb out the roots so you can see their full length.
Trim the roots of your tree back. Trim at least 50 percent of the roots. However, you can trim as much as two-thirds of the roots away for bonsai, without adversely affecting the health of the azalea.
Place the tree in your bonsai pot. If you still have some roots that extend beyond the pot, either fold the roots into the pot or clip them off. You may need to use some heavy-gauge bonsai wire to hold the tree in the pot. If you do, remember to remove the wire after a few months, to avoid damaging the roots.
Fill your bonsai pot with a commercial bonsai soil mix. Do not use potting soil, bonsai mix is optimized for small pot growing.
Look at your tree from multiple angles once your azalea is in its pot, to decide the best way to approach pruning.
Prune your azalea from the bottom up and from the inside out. Open up the azalea so that sun can reach the interior leaves. You can safely remove between 50 and 75 percent of the tree's foliage in this initial pruning.
Wire the branches once you have pruned the tree. Wire the branches by wrapping the wire at a 45-degree angle to the direction of the branch. If a single strand of wire does not properly hold the branch in place, double or triple the wire by making additional wraps adjacent to the first wrap. Bend your branches into place slowly, so you do not break the branches.
Water your bonsai every two to three days. Do not allow the soil in your azalea to dry out.