A Brief Tutorial in Pinching Japanese Maples

This 20-year old Japanese Maple has never been pinched. Freely grown, a maple will have a coarse shoot structure, but this early period of no pinching develops the trunk and branches and roots.

Pinching a maple when young stunts development.

This Japanese Maple might be pinched this year. The branching is past tertiary and has good structure. 

A Japanese Maple shoot about a day away from opening its first leaves. 

Push the first pair of leaves apart with a tweezer, grab the interior shoot, and pull off. If you catch it right here, the internode will be shorter.

This is some of the first bonsai work we do after spring repotting.

This shoot has elongated several days past ideal, though it should still be pinched to the first set of leaves. As this is a single flush plant when mature, we get one chance a year to shorten the internode. 

A note of patience:

When first pinching a specimen, it will likely have a thicker twig. This translates to a couple years where even if you pinch, it will have a longer internode. Keep at it and you can get a thin twig, with a short internode. This offers the delicacy Japanese Maples are known for. 

A maple following years of pinching. Notice the thin twigs and short internodes.

There is a point at which pinching goes the other way. The first pair of leaves open to no shoot inside. If that goes on, those branches may die back. No shoots elongating is our clue to fertilize more. 

When should we start pinching?

Some will pot-grow their Japanese Maples 10-30 years before pinching. There are also those who prefer a stronger tree and never pinch—a possible direction for those in stressful climates for Japanese Maple: hot and dry with little winter cold. This is likely to stress them and leaving longer shoots may be best.

In some situations pinching is useful to rein in this coltish species, especially for small specimens like shohin.

Many find Japanese Maple a tough, forgiving plant. Pinching is maybe best thought of as optional, and applied dependent on goals.