You may remember my wonderful Willow oak, Quercus phellos, from this photo I took last fall. I repotted it last spring, and cut back the lowest right branch hard to improve it, and from there just did some light pinching and pruning through the growing season.
This tree has exhibited an unusual characteristic since I brought it home, namely, it’s the last of my trees to come out each year. Typically this is in mid- to late-April. I’ve been watching it closely since things started budding in March. Nothing. So I began to wonder if the tree had, for some reason, died over the winter. We certainly had some cold weather, but it’s been through colder weather than we had this go-round. Of course, you never know for sure what might do a tree in.
Two days ago I finally spotted some green on a bud.
Willow oak buds are not inconspicuous, but they lie flat against the branches and look more or less desiccated. It’s not until the alarm goes off that they swell and you can see green color and bud scales. I had one bud on the 10th, and by the 12th the tree was full of swelling buds. Rip Van Winkle was waking up. My Willow oak was alive!
This brings up something every bonsai enthusiast faces. How do you know when a tree you just collected, or one that has come through a rough winter, is really and truly dead? Are there any telltale signs? How long should you wait before yanking the thing out of its pot and tossing it unceremoniously on the skeleton pile?
First things first. When collecting new trees, the goal is to get them into nursery containers, tubs or grow boxes as soon as you can. Typically you won’t have a large root mass on a newly collected tree, and typically you won’t have any roots until you see the tree pushing shoots. Preceding this is the appearance of trunk buds. For the most part, once you see trunk buds the tree has at least a 90% chance of survival – provided you don’t hinder the natural recovery process. This means you don’t move the tree around or otherwise do anything to damage newly emerging, tender roots. It generally takes several weeks for these new roots to harden off, and you really don’t want to move the tree from the container it’s in until the next growing season at the earliest.
Circling back to the newly collected tree, what are the telltale signs of life or death? This varies from species to species. Most will show green when scratched – this is the cambium layer, which is chock full of chlorophyll that does not break down during fall and winter. Hackberry bark remains green, at the surface, for many years. Older Bald cypresses typically don’t show green when scratched, a peculiarity of the species. With that said, many younger ones actually show green at the surface of the smooth areas of bark. Sometimes you see it, sometimes not.
If you’re gauging life or death by the scratch method, be aware that there’s “juicy green” and dry green. Dry green is more or less self-explanatory; there’s no shine to it. Juicy green is a bit tougher to gauge, but once you’ve got a little experience you can easily see the difference. Now, I’ve seen many specimens that scratched juicy green for an extended time, only to eventually dry out. This can be a lengthy process, by the way.
Another telltale sign is brittle branches and branchlets, for those species that retain the branchlets through winter. Not all species do. Typically a tree that’s alive will maintain very flexible branchlets – my Willow oak did just that, so I remained mostly optimistic (on even-numbered days, alternating with pessimism) even after the April “deadline” passed. Now, don’t use the flexible branchlet sign as your be-all end-all when determining life or death; in harsh winters, some trees will lose branchlets and even small branches they might not otherwise, and then come back in spring.
What’s the bottom line? Give your trees every chance when spring gets here. Hang onto them as long as there are signs of viability. You never know when old Rip Van Winkle will wake up.