Kempinski’s Korner – September 2022

Developing bonsai – fall activity

As we hit our fall growth spurt (that’s right in September and October you will see your tropical trees go into a mini-growth spurt as the temperature goes down) it’s time to think about refinement.  For trees in stage 3 and 4 (If you don’t know what these stages are I suggest you get my book, Introduction to Bonsai – Growing and Appreciating Bonsai Across the Globe, available on Amazon) you can perform some important tasks in now.

For tropical trees extending branches to get an evolutionary leg up by making as much photosynthesis as possible get to work.  Here are some guidelines to trim a branch now right before the spurt so that you can get new growth to develop ramification and a good structure.

  1. Always trim inside the final canopy.  By that I mean trim the branches shorter than you intend them to be in the final design, as the branches need volume to grow.
  2. Follow the basic rules about branch placement but don’t be a slave to them. If you need to break a rule go ahead and do it.  You can always cut a branch off later.
  3. Remove small branches near the trunk, unless you need that branch to grow into a future larger branch. The goal is to have the foliage on the periphery of the canopy. 
  4. Trim to bifurcated a node; that is branching of two.  It cleans up the tree, prevents unwanted thickening and make it easier to wire.
  5. It is ok to wire branches you have trimmed. Now is a good time to check the wire you may have placed earlier in the year to see if the branch is starting to grow into it.  Remove this wire and rewire as needed.
  6. Sacrifice branches should be left alone to develop whatever part of the tree you are trying to develop.
  7. Avoid repotting trees this time of year.  Tropical trees do best when the evening temperature is about 70s for at least 2 months.
  8. Fertilize with granular fertilize.  This is especially key with all the rain we have had, as the old fertilizer has been washed away.
Premna obtusifolia prior to fall pruning
Headache Tree, Premna obtusifolia, prior to fall pruning.
Same Headache Tree, Premna Obtusifolia, after pruning inside future canopy
Same Headache Tree, Premna Obtusifolia, after pruning inside future canopy. The red clouds show the future outline. X indicates future removal of a sacrifice branch
Premna Obtusifolia, with sacrifice branches
Tall Headache tree, Premna Obtusifolia, with sacrifice branches down at the bottom to add thickness to the base. These will grow unchecked for several seasons.
Chinese Elm, Ulmus parvifolia, prior to pruning showing sacrifice branch
Chinese Elm, Ulmus parvifolia, prior to pruning showing sacrifice branch, which is really the number 1 branch to thicken up. I grew this tree as a cutting in the ground for about 15 years
Red lines show future canopy for this chinese elm
The red lines show future canopy for this Chinese Elm. Note how the tree is nowhere near its final canopy size.

Rob Kempinski

Rob is an internationally recognized bonsai artist and author.  He enjoys teaching bonsai at all levels and introducing newcomers to the pleasing art of growing miniature trees in a container.  Rob has written many articles for bonsai magazines and journals.  He has published several books, many on the art of bonsai.

Rob's Texas Sage
Rob Kempinski showing his Texas sage

Bonsai Society of Brevard

For more detailed information contact our Brevard based Bonsai club.

The Bonsai Society of Brevard is one of the many clubs within the Bonsai Societies of Florida.