What does fall mean to you? Leaves turning, growth ended, prelude to winter? That’s all true, but for most of us (perhaps more of us in the South) some of our trees may still be pushing growth. This is particularly true if you’ve done any recent root work on them. Trees respond in a reliable fashion to having their roots disturbed at any time of year – they grow new roots, and if also pruned in the top grow new shoots. Here are a couple of examples from my own benches:
I wrote about this Water-elm, Planera aquatica, on September 29th. I had lifted it from my growing bed just to have some fun. It had a nice base and a perfect trunk form to produce a great broom-form bonsai. Do I normally lift trees in September? No, but my scientist background makes me want to experiment with trees so you never know what I may do. Up came this one, it got its root-pruning and went straight into this Chuck Iker pot.
I knew at the time that this tree would respond to having its roots and crown cut back hard by producing new growth. It took a few weeks, but lovely new buds began to form on the trunk and before you knew it I had some shoots that were several inches long. Today I wired a couple of them so I could start the shaping process. It sure doesn’t look like much right now, but I can assure you that next year I’ll be able to create the entire structure of this neat little bonsai.
But here’s the critical question: is there harm in doing things to your trees at this time of year that force it to produce growth usually reserved for spring? In my experience, the answer is no. Trees “want” to live, just as you and I do, so doing the hard pruning in summer or even early fall doesn’t really change that. Since deciduous trees store food in their cells over winter, and since sap stops flowing over winter, the only thing the tree needs to do after a late-season pruning is to produce some new roots and whatever top growth it can.
But what if a freeze comes along? I’ve seen this happen too. Because of where I live, some species will continue putting on growth well into November. We get our first freeze down here in December, typically. When it comes, any tender growth that can’t hold up to the cold simply gets burned back and that tends to finish off the growth for the season. Then the tree comes back out in spring. I’ve never seen a case where a tree, which didn’t have a fundamental health issue to start with, failed to come back out the next spring.
Here’s another tree that I pushed the envelope on, a Cedar elm, Ulmus crassifolia. It was lifted from my growing bed on October 15th. You can see in this photo that in only three weeks the tree has pushed a lot of new growth. I know beyond a shadow of a doubt that I have a lot of new root growth as well. So the tree wanted to live and responded accordingly. It will continue to grow for the next few weeks or more. The new growth will harden off to an extent. Then winter will be upon us. And I have every reason to believe that the tree will not skip a beat in spring – in fact, lifting it this fall will give me a head-start on developing it for sale in 2017.
Do you have any experience lifting trees in fall? I’d love to hear any feedback you might wish to share.