Freeze Damage in Bonsai (& other woody plants) 10/13/15

NCsnowThis luscious planting resides at the North Carolina Arboretum. The photo was put up on the Internet Bonsai Club forum by Arthur Joura. The caption reads "This planting is one of a small handful in our bonsai collection that consists entirely of plant material that can tolerate the extremes of winter, and so it remains on the bench, on display in the Bonsai Exhibition Garden all through the year." The statement 'can tolerate the extremes of winter' makes sense if you live someplace like North Carolina, but not if you live someplace like Vermont.

Our Vermont fall foliage extravaganza is winding down. Most of the leaf peepers headed home yesterday. I’ve already moved some of my smaller trees onto a covered porch. Another month or so most of them will be winter storage.

This post is from last December (edited some now). It’s important enough to repost every year about this time, so we’ll do just that.

Thanks to a tip from Elandan Gardens, I recently came across an Evergreen Gardenworks’ article by Andy Walsh that was adapted from an Internet Bonsai Club post. It’s titled ‘Freeze Damage in Woody Plants.’

We’ll just show you the beginning of the article and encourage you to visit Evergreen Gardenworks for the rest.

Freeze Damage in Woody Plants
by Andy Walsh

Evergreen Gardenworks’ Introduction

This article is adapted from an Internet Bonsai Club post. In it, Andy discusses the physical and chemical changes involved when plant stems and roots freeze. This kind of information is crucial to constructing cold weather protection for many areas of the country. Some slight editing has been done to make it more readable in this context.

The Three Stages of Freezing

First off, several times here writers have stated that their trees are frozen in the winter and survive. It’s clear to me that there is great misunderstanding around what some people think when they say a plant is frozen. If a plant truly freezes it dies. The formation of ice within the cells of a plant is invariably fatal. What I think many people see in winter is the soil of their trees frozen and they equate this with the plant being frozen. This is not the case.
From my readings, there are basically three stages of freezing that can be observed with, and have significance to, a Bonsai:

The freezing of the water in the Bonsai’s soil.
The freezing of “inter”-cellular water in the plant’s tissues.
The freezing of “intra”-cellular water in the plant’s tissues.

Here’s your link to the rest of the article.

 

Goshinsnow

John Naka's famous Goshin, fully adorned. The Needle junipers are plenty hardy in Washington DC where the tree resides at U.S. National Bonsai & Penjing Museum.

 

snow31

You can leave hardy bonsai out in the open here in northern Vermont for quite a while, but sooner or later they'll need some serious protection.

 

NCRoan Mountain landscape again. Fortunately, winter will end someday.

 

b1satsukiSpeaking of Azaleas (the little flowering trees in the planting just above), this definitive Satsuki Azalea book will soon be gone and there are no plans to reprint.