How to Trim Bonsai Root Systems

Caring for a Bonsai tree is not terribly time consuming. Shaping, pruning and overall tree health should be your focus. Bonsai maintanence includes cutting back the root system every two years or so. If the tree becomes root bound, it will perish or grow too tall to remain a Bonsai.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Wire
• Screen
• Clippers
• Soil
• Water
• Fertilizer

1. Note the day on which you trim the root system of each tree. This will help you to keep track of when it should be done again. Don't rely on memory, especially if you have many trees.

2. Moisten the soil in the pot. Try to get the Bonsai out without breaking branches or damaging roots that you don't wish to discard. Wet soil doesn't stick to roots like dry soil.

3. Grasp the tree by the thickest part of its trunk. Gently wiggle the tree until the soil and the tree come out of the pot. Place a bucket filled with approximately two inches of slightly fertilized water next to the pot.

4. After the tree is removed from the pot, gently put it in the basin or pail of water. Gently wash the root system by tossing handfuls of water over the roots. Make sure to keep the roots wet. If you must take a break, leave the roots in the water.

5. Notice a thick root near the center of your Bonsai. This is the tap root and should only be a few inches long. If the tap root is, say, six inches long, cut off three inches. If a tap root gets too large, the tree will grow higher.

6. Once you have clipped the tap root, check the other fibrous roots and trim back the thick ones. You want the plant to have room in the pot.

7. Set the tree in about an inch of soil that you saved from the pot after the roots have been trimmed back. Make sure to put a screen over the drain holes in the pot and some small rocks over the screen. Then add soil until the truck is at its previous level. You might have to wire the tree into the pot.

8. Add some water and fertilizer into the soil and gently pat the soil down. Make sure the tree stands straight without support. For the next few days the soil should not be allowed to become dry. Don't soak the soil, but keep it moist. Don't put the tree in harsh sun.

Tips & Warnings

• Handle the tree carefully.
• Don't be shy about cutting back the roots. You are looking for a small tap root and very fine fibrous roots that don't crowd the pot.
• Keep the soil moist while the tree is in shock.
• Don't trim branches at the same time you are trimming roots.
• Try to get the same soil consistency you had before you cut back the roots.
• Always keep the roots wet or moist during the entire procedure.

Resources

• A website for the novice to expert Bonsai enthusiasts.
• The Bonsai Clubs International web site.

[Glynis]

on 9/12/2007 Hi, thanks for this, very useful. Wonder if I might use the image to explain this to our visitors? I'm a volunteer at the Botanical Gardens & Glasshouses, Birmingham, England, at the moment I'm designing a sign and information sheet for the Federation of British Bonsai Society's collection held here at the Gardens. I do understand if you would prefer I didn't use it.