How To Prune Bonsai Trees

Bonsai trees need training throughout their lives in order to:
1. Maintain the small size of a naturally large tree
2. Give the plant an appearance of age and maturity


Pruning Tools:
Pruning instruments should always be sharp and clean because blunt tools will leave a ragged stump, which could easily become a doorway for disease and pests. Heavy pruning cuts should be whittled down to a slight hollow in the trunk or branch in order to encourage the formation of a callous. Large cuts should be painted with protective paint.

When pruning a branch, try to make the cut just above a bud that is pointing in the direction you want the branch to grow. If the cut slopes downwards, then the water will run off and the chances of rot will be considerably lessened.

Main branch pruning:
Heavy pruning should be carried out in autumn, winter, or early spring, and is the major way of shaping a bonsai tree. The main priorities are to remove any branche that is too low at the front 1 any branch directly opposite another 2 any that creates a so-called cartwheel effect 3 and any that crosses the front or back to the other side of the tree. 4 Hollow out all stumps with a sharp knife 5.

General Pruning:
Throughout the growing season, cut back shoots of maples1zelkovas2and other broad-leaves to the first or second pair of leaves. Pinch out the tips of juniper shoots 3. With pines, 4 remove the center "candles" and pinch back the others.

Leaf Cutting:
Do this in early summer on deciduous trees that donot flower or fruit. Use sharp scissors
to remove half of each leaf1on weak branches or trees, but all but the stalk 2 on strong wood. In a few weeks the stalk will drop and new small foliage and shoots will grow.

Size Classifications

Additionally, bonsai are classed by size. Sizes of Bonsai include:

• MAME Tiny Bonsai
  • KESHI-TSUBU up to 2.5cm
  • SHITO 2.5-7.5 cm tall.

• SHOHIN Small Bonsai
  • GAFU 13cm-20cm
  • KOMONO Up to 18cm
  • MYABI 15cm-25cm

• KIFU medium Bonsai
  • KATADE-MOCHI Up to 40cm

• CHU/CHUHIN Medium to large 40-60 cm tall

• DAI/DAIZA Large Bonsai
  • OMONO up to 120cm
  • BONJU Over 100cm Tal

Note that sources disagree on the exact range of sizes given for a category.

There are a number of specific techniques and styles associated with mame and shito sizes, the smallest bonsai. These are often small enough to be grown in thimble-sized pots, and due to their minuscule size require special care and adhere to different design conventions.