Satsuki Azalea After-Flowering Maintenance

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?

1. 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.
2. 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.

Two whorls of shoots grew from the ends of previously trimmed Y-shape tips.

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.

Flowering of a Chinzan Satsuki Azalea – Murphy’s Law

I started this ‘Chinzan’ satsuki azalea from a nursery gallon plant about 17-18 years ago. It was grown in a flower bed for about 7-8 years, lifted and trained as a bonsai in a pot since then.

I prepared this tree for the April 11-14 American Bonsai Society Convention hosted by the Houston Bonsai Society, and expected it to have partial blooms based on past experience. Unfortunately we had several days of unusually cold weather in late March; as a result the Chinzan was covered with swelling buds but not a single bloom during the show. A week later, flowers started to come out and had about 80%  blooms by the following week. So it went from a tree with no flower to fully covered with flowers, but only after the show! A bummer.

At the show on April 14, 2019.

Professional azalea growers use plant growth regulating hormone such as gibberellic acid and greenhouse temperature to control flower blooms for sale on special occasions. We, hobbyists, have to rely on past experience when did flowering occurred, mother nature, with little or no control over the exact timing of flowers except crossing our fingers. Hind sight, I should have sprayed it with gibberellic acid which I have at home, and hoped for the best. May be worth to experiment to gain some knowledge.