Tree Tips

March 2026

Bonsai events and shows

This Saturday and Sunday is the Mammoth Fundraiser In Oakland at lake Merritt. Don’t miss the auction (Sat) and sales (Sun) as you can get supplies and trees from a vast number of vendErs. 

We have the Cupertino Cherry Blossom Festival coming up the weekend of April 25-26. 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 enjoy working on trees the entire time, while people come by to admire our bonsai display and ask questions about our art form.  

the beginning of spring

A different rainy season so far with intense downpours and long dry periods. We’ll see how it pans out going forward.  

The weather has been unusually warm and many trees are one or two weeks ahead of their normal schedule.  Most trees are popping and we only have a short window open to transplant beeches, hornbeams, boxwoods and conifers. My boxwoods are in flowering mode and are setting fruit. 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 won’t have to deal with frost damage on new tender foliage.    

ongoing repotting

Continue re-potting on your elongating species like conifers. But don’t bare-root conifers. 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 be able to 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 in 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.   

Broadleaf evergreens such as boxwoods and azaleas as well as junipers, and pines are repotted in February and early March. Needle juniper is an exception - that can wait till April or May.  

And remember to secure all trees in the pot with tie-down wires! If the tree is wobbly it will not develop lateral roots, but instead put down one or more tap roots again. Not what we want.

the shifting sun

At this point, return your transplanted trees to a sunny location unless you have done major root work. The angle of the Sun is relatively low yet and it will warm and stimulate the roots and 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. 

general seasonal care

You can begin styling and wiring your conifers. Big bends are O K 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. Not on mature trees 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.🌳