Tree Tips
March 2025
We just finished the Mammoth Bazaar weekend with the auction on Saturday and sales on Sunday. We have the Cupertino Cherry Blossom Festival coming up the weekend of April 26-27. Keep that weekend open and start working on a tree you’d like to show. It’s one of my favorite activities each year. I work on trees the entire time while people come by to admire our bonsai display and ask questions about our art form.
This Thursday, however, we have a demonstration with Bob Shimon, who will be working on a Pygmy Cypress at the Good Sam church. Hope to see you all there! For years, Bob has been a collector and vendor of redwoods, cypress, and oaks in the logging areas around Point Arena, where he lives. It should be a great opportunity for us all to learn how to deal with this rare tree.
The rainy season has been spotty so far, with intense downpours and long dry periods. We’ll see how it pans out going forward.
Most trees are budding, and we only have a short window to transplant beeches, hornbeams, boxwoods, and conifers. My boxwoods are flowering, and the maples are chomping at the bit. Be careful with aftercare if the leaves are showing on your deciduous trees. Hopefully, we won’t have any cold snaps going forward, so we can avoid frost damage on new tender foliage.
Continue working on your elongating species like conifers, but don’t bare-root them. You could lose them. If there is any field soil, it must be removed, but if it is solid throughout, do half of it this year and the other half two years from now. The half you do this year will support the tree when you clean out the other half in a year or two.
If ANY tree has a good, solid root mass with radial roots and is free of field soil, don’t bare-root it. Just cut back the exterior and bottom edges and clean the surface at a slant, down from the trunk to the outside edge of the root mass, but leave the healthy core soil alone. Be sure to cover this with new soil at the end.
Remember to secure all trees in the pot with tie-down wires. If the tree is wobbly, it will not develop lateral roots but will try to put down one or more tap roots again, which is not what we want.
Broadleaf evergreens such as boxwoods and azaleas, as well as junipers and pines, are repotted in February and early March. Be careful, but this year we can extend a little as the weather is cooler and the rains are still coming. Needle juniper is an exception; that can wait until May.
At this point in the year, return your transplanted trees to a sunny location unless you have done major root work. The angle of the sun is still relatively low, and it will warm and stimulate the roots to get them going faster. Rotate all trees every couple of weeks or at least monthly for well-rounded growth. Try to space them on your tables so each gets unshaded light from all angles. Again—do watch out for late frosts. The weatherman always has a curveball in his bag of tricks.
You can be styling and wiring your conifers. Big bends are okay until about the end of March. After that, you run the risk of detaching the cambium from the sapwood.
Don’t fertilize yet, except for trees you want to fatten and young material in a pre-bonsai state. Avoid fertilizing mature trees that you are refining.
Remember to continue your monthly fungal treatments, alternating different fungicides like copper, Mancozeb, Zerotol, Clearys 3336, Daconil, etc. You need to mix it up for all those nasty fungi. 🌳
