The best part of growing satsuki is when they are in full blooms but they only peak for about two weeks and then begin to decline. When 30-40% of the flowers have faded, it is time to remove all the flowers, fertilize the tree and do the after-flowering maintenance work.
Why the After-Flowering Maintenance?
- Flowers use up a lot of the tree’s energy. It is better to remove all of them, including the unopened buds, when 30-40% of the flowers have faded. Fertilize the tree to thank it for putting out a good show, then selectively trim back shoots and branches to improve air flow and allow sunlight into the interior.
- The purpose of trimming shoots is to control growths, force back buddings and improve ramifications. One can select which branch to trim or which one to allow continuous growth to improve the overall tree structure.
I will use this 4-5 year old Osakazuki grown from a cutting to show how the shoots are trimmed after flowering.
Trimming Whorl Forming Shoots
Azaleas tend to develop a whorl of several shoots coming out from a single point. For ramification we only need to keep two shoots at each branching point.
Four shoots of the right side whorl were cut off, either with scissors or broken off by bending them backwards with fingers, leaving two with similar strengths.
The left one has three shoots; the center shoot was removed leaving a pair of Y-shape shoots.
You can stop here for a young seedling still in development and allow the pair of Y-shape shoots to continue growing.
If your tree is in an intermediate developmental stage, you can trim the shoots further back leaving two leaves on each axil. This removes auxin at the growing tips and forces back budding, two new shoots will grow at the petioles and create ramification.
What if the shoots are still too long after cutting back to two leaves? For a healthy tree, you can trim further back without leaving any leaves on the shoots to get more proportional ramifications.
Let’s say you want to have an even shorter internode, all you need to do is cut further back to last year’s wood to force new growths. Although one can cut back to old wood during the active spring growing season, it is always safer to leave a few leaves behind to avoid possible branch die back.
Putting These Into Practice
How much to trim after flowering depends on the developmental stage the tree. There is no need to do anything for a young seedling, just let it grows. If the tree is ready for styling and you want to have some controls on how new shoots grow, then do the trim back described above. The tree will look like a plucked chicken after trim back but new buds will come out soon and the tree will be full again later this year. See my old post One-Year Progression of A Shohin Chinzan Satsuki Azalea Bonsai.
If the tree is already well ramified and is in a show quality stage, the same principles apply. The after-flowering maintenance is like giving the tree a new hair-cut to maintain the outer profile, remove dense foliage to check on wiring, allow light and air to filter into the interior. I usually feed the tree with fertilizer for couple of weeks after removing the flowers before the trim back.