The azalea is one of the very few tree species that are basally-dominant. This means that the lower branches grow stronger than the weaker top, which leads to the shape of a shrub in nature. Therefore, prune the branches at the base harder than the top. The Azalea withstands strong pruning very well and even produces new shoots from branches on which no leaves are left. Immediately after flowering the wilted flowers and ovaries are cut off or pinched by hand. This point of time is also favourable for all other pruning and trimming works because in summer the new flower buds for the next year will develop. If you prune your tree too late there will be no or nearly no flowers in the following year.
Unwanted shoots from the trunk or the base of the branches can be removed at any time of the year.
Extensive styling works on the raw material are often done in spring and, in that case, flowering is omitted consciously.
The wood of the azalea is brittle so that wiring and bending should be done with great care.
Once trained to a specific bonsai shape, azaleas require only maintenance pruning and trimming. Remove spent flowers as soon as they wilt and any new shoots that develop after blooming ends. Pruning secondary shoots until late July helps the bonsai hold its shape. In the fall, you can trim out the inner leaves to improve the next season’s flowering.
Azalea pruning is no big deal, normally the dead blossoms are pinched rather than cut, though. This is known as ‘deadheading’ and encourages bud-set for the future. A few seasons of this can lead to a plant/tree producing such a profusion of flowers that there is almost no foliage to be seen during blooming.
During pruning it’s best to clean out the smaller interior and crossing branches at that time, allowing more light in. The best way is to cut back a little further than you would think because it will force budding and breaks at the branch apex thus, more foliage.