Five years ago I asked here about ways to train this ash (Fraxinus excelsior) seedling into a bonsai. The little ash bonsai has now grown and it's in his 4th year. See the photo below. Any suggestion on how I could limit leaf size at this stage? Or should I leave it to grow to its final trunk/branch shape first?

  • A simple google search brought me too: evergreengardenworks.com/leafsize.htm but I am not experienced with such matters (learning bonsai myself) so perhaps you have already seen this page.
    – Rob
    May 14, 2019 at 17:04
  • What also helps is to put it in a bonsai pot (scale), the plant will get used to the small size and will react by keeping above ground also small (you'll have to help by pruning). And have patience... 4 years is nothing in bonsai terms.
    – benn
    May 15, 2019 at 9:56

1 Answer 1


Basically, there are only 3 ways to make small leaves.

  1. One is to keep the tree very small, that is as a mame/mini bonsai, which clearly isn't what you are wanting to do.
  2. Second is to cut the compound leaves back to just 2 leaflets, 4 leaflets, etc., and by then removing one more leaflet, you can make odd numbers
  3. Lastly, you can defoliate. The new leaves are small and over time may enlarge to full size. Were you do defoliate in August, say, they may not attain normal full size before leaf drop. This, however, seriously weakens the tree.

It is also possible that the leaf size will reduce somewhat in bonsai culture. Many species leaves progressively 'shrink' over the seasons with roots confined in a small pot (what gardeners call 'root bound').

In brief, do #2.

Ed. in response to questions about what #2 means:

This whole thing is one leaf, the compound leaf of ash. I've marked red lines where you may cut it to illustrate. enter image description here Since the normal leaf has one leaflet at the end, cut leaves may look 'unnatural', which you can correct to a certain extent by also removing one of the leaflets on either side of the cut.

  • Can you describe in more detail #2? I am not sure I understand what to do... May 14, 2019 at 20:18

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