Bonsai is the horticultural practice of creating a miniaturized but naturalistic representation of a tree in a pot. Ryan Gugeler, bonsai artist and collector of over 30 years, brought in a Blue Alps Juniper (Juniperus chinensis 'Blue Alps') that he had started from a nursery pot over a year ago. This was the tree’s second session of trimming and wiring. As Ryan worked, the crowd asked some really great questions about the general care and maintenance of bonsai, of which I will recount below:
Trimming - Generally, trimming takes place once a year. Be sure to do the entire plant at once as this encourages an even growth pattern all around the plant. Don’t be afraid to trim back hard. Plan for future branches that can be wired into a place.
Wiring - On a juniper you can use copper or aluminum wire. Remember to wrap the wire clockwise if you want the branch to move left and counterclockwise if you want it to move right. You want the wire to be fairly tight, but not enough to strangle the branch. Expect the wiring to live on the tree for a year.
Potting - Use a lightweight, porus mix of pumice, lava and akadama fired clay. Use a screen to filter out finer particles to prevent compaction. Juniper can handle a more coarse potting mix, and deciduous trees will prefer a finer one. There should be no soil or other organic material in your bonsai mix. Consider repotting conifers and deciduous trees only after 5 years, and tropical trees can be repotted after 2 to 3 years.
Watering - Because the potting mix is very porous and doesn’t hold water, you will need to check on your bonsai every day. Ryan will often water his twice on very hot days.
Fertilizing - Fertilize only during the growing season. Ryan makes his own “cakes” that slowly release with each watering. In the fall growing season he switches to a 0-10-10 that encourages root growth but not foliage.
Overwintering - During the winter the main concern is overexposure to wind. Ryan will place all his plants together in their pots on the ground and get them as close together as he can. During freezing weather water once you hit a thawing temperatures - and only then about once a month.