Spring has sprung, and I hope the good weather remains (It won’t, forecast is for 14F for Tuesday.) But we are still going ahead and repotting and root pruning.
I recently sold a developed Japanese maple bonsai. The new owner asked about root pruning and I mentioned we often use a reciprocal saw to simply remove the major portion of the roots on established or pot bound trees. Simply slicing the roots off does less strain on the tree than picking away old soil with a wooden chopsticks for hours. Before potting, we of course use sharp trimming shears to make clean cuts. We do NOT use our old trimming shears because they are usually dull.
A few years ago we transplanted a Trident maple forest on a granite stone that Yuji Yoshimura created many, many years ago. The roots were so thick and powerful they pulled the hydraulic cement off the rock. It actually was just sitting on the rock and we often raised it to water.
One sunny day in MAY we decided to repot the group into a bonsai container. Please note the tree is in full leaf. Out came a reciprocal saw and two friends simply sliced the roots while I was supervising.
The tree was immediately potted and placed in the shade for a couple of weeks. The tree never realized what happened and continue to grow vigorously, even though it only has four trees which have now grown