Perhaps the greatest difference between high-quality bonsai and bonsai that are just potted trees is the correct application of technique in the correct circumstances. It sounds so simple to make a plan and execute it using the best techniques available; but, the difference is all in the details.
While visiting the nursery of Shinji Suzuki in Obuse, Japan, I noted a large number of older Ume (Japanese Flowering Apricot) that were in the greenhouses. The trees had old, rotten trunks like so many ume seen in Kokufu, but these trees were not ready for show. Upon closer inspection it became apparent that the trees were undergoing a remodeling process, most likely to correct branches that had become too long and leggy.
In my own experience with Ume I’ve become frustrated by the seemingly difficult task of getting good ramification. I’ve had a few discussions on the topic; multiple people had mentioned that grafting the trees was a common practice in Japan. For an excellent overview of Ume see Peter Tea’s 2012 post, “Japanese Flowering Plum Basics.”
Recognizing the difference between the bud types turns out to be the key to cutting back. But hard cutback is seldom productive in my experience as the trees frequently give up on branches that you chose to keep in favor of new buds from strong nodes behind them. To overcome that problem, and also to possibly change flower type, grafting is the logical technique.
Peter’s 2012 post mentions that February and September are the best times to graft Ume. Some questions and experimentation remain before the technique will be clear to me. We’re left to discern what the ideal timing of cutback is for the old branches when grafting. From the trees I observed in Suzuki’s nursery it seems that the old branches are cut off within one year of the grafts beginning to grow. This seems logical, since in my own experience the tips buds on ume grow much more quickly than the smaller buds back along the branches.
The most important thing to take away from the observation for many people is that grafting ume is an established technique that should be used to your advantage. Whether you’re trying to improve the position of branches, or change the flower color, don’t hesitate to try some grafts to improve your trees.