Before starting any work, in my opinion, it is important to understand why you are doing this and what processes are happening. Yes, and the consequences of their actions do not interfere with remembering. So today I wanted to share my thoughts on such a controversial garden operation as whitewashing trees. I think 99% of gardeners have done this at least once in their life. In this article, we will analyze what benefits spring whitewashing of trees brings (and does it bring?), And with what can it be replaced.To whiten or not to whiten? Do I need to whiten trees in spring?
In my school and student years, it was, in general, an obligatory procedure, and during the so-called "Leninist subbotniks", which means at the end of April. But honestly, even then, "vague doubts" began to torment me. Well, yes, it seems beautiful and elegant, but to the question “why?”, The teacher quite reasonably answered - to kill insect pests. Although all sorts of insects at that time were already flying in the air around flowering trees (it was in the south).
Later, seriously carried away by gardening and reading literature, I learned that whitewashing also kills diseases spores, is a means of protecting trunks and skeletal branches from frost pits. And you need to do it twice - in the fall and spring. In general, I read a lot in different ways, but the real work in the garden put everything in its place, at least in my head. So, in order.
Whitewash against pests and diseases
It is well known that with the onset of the cold period, many insect pests, and also beneficial ones, are clogged in the cracks of the rough bark of mature trees and winter well there. Some lay their eggs right on the smooth young bark. These eggs are protected by a dense shell and tolerate winter well. Spores of many diseases can also winter on the surface and in the crevices of the cortex.
So whitewashing in the fall may well be beneficial. But only if you clean the old bark a little before whitening, removing only easily removable parts of the bark, and then ... ATTENTION! Whiten the whole tree, from the ground to the crown. After all, if you whiten only, as my neighbor does, to a height of 1 meter, then you will kill all sorts of wintering "parasites" at this height. And the rest will survive well and begin their malicious activities in the spring.
Therefore, to combat them, various drugs and methods have been developed that are more or less effective. Say, late autumn rooting and early spring spraying with strong solutions of insecticides and fungicides on bare, dormant trees. And whitewashing will not help here.
About eradicating spraying, read the article Where garden pests winter and how to ruin their life?
Whitewashing as protection against frost pits
For those who are not in the know, frostholes appear at a time when sharp fluctuations in day and night temperatures occur in nature. Usually, this is the end of winter, the beginning of spring. It all depends on the region and climate, there are places where this can happen in the midst of winter.
The essence of the phenomenon is that during the day the rays of the bright sun fall at the right angle on the dark trunks and branches of the trees and warm them very much. And after sunset, the night frost takes matters into their own hands. Such temperature differences can reach 20 degrees. The bark of trees, as in that song: "She is thrown from a fiery hearth into a chilling cold ..." And as a result of a sharp temperature difference, it bursts.
What does the whitening have to do with it? Gardeners are trying to somehow smooth out this temperature contrast, making it less painful for trees. We are not able to reduce the night frost, but we can reduce the daytime heating of trunks and branches by applying a layer of something white, reflective on them.
Moreover, it is possible to protect from heat selectively, only vertical branches and branches that are at an angle of about 90 degrees to the rays of the low winter sun and which are very hot.
Now, understanding why you really need to whitewash the trees, it is worth discussing when and how to do it better.Whitewashing helps smooth out the contrast of day and night temperatures, making it less painful for trees.
When to whiten?
Since the process of the occurrence of frost pits mainly occurs at the end of winter and the beginning of spring (it all depends on the region), it is logical to whiten trees just before this period, around the beginning of February. That's just not everywhere it is physically possible.
It is good if your garden is in the southern region, where thaws occur, and you can get to the tree, and bleaching is recommended at plus temperatures. But in the northern regions, where the fallen snow lies around the trees in a thick layer and the frosts do not let go even for a day, whitewashing should be done ahead of time, from autumn.
Read more about autumn whitewashing in the article Autumn whitewashing of fruit trees.
By the way, in the southern regions it is whitewashing from the autumn that will allow you to sleep peacefully and not worry that you missed the right moment. There is only one, but a big problem. Ordinary lime whitewashing will not last on the bark until the right moment, and most likely, by the end of winter there will be no protective effect from it.
What to whiten?
There are various options for whitewashing. Someone uses lime, someone more gentle chalk, someone adds clay, straw and manure to create a more durable coating. Someone adds copper sulfate as a fungicide to combat pathogens, someone brings an element of modernity - PVA glue to the usual "grandfather" whitewash. Such whitewashing, indeed, holds well all winter. And someone boldly uses white water-dispersible and acrylic paints from construction stores.
However, here I would like to note that in all these recipes the emphasis is on the durability of the coating, but no one is interested in how a tree feels under a layer of clay or under a film of PVA glue. After all, as I said, it is advisable to cover with whitewash and standard, and all branches that are potentially at risk, and this is a large area.
A tree needs air exchange with the environment, and all coatings reduce this air exchange to one degree or another. All these whitewashes are not natural, but an element introduced by man.
But in garden shops you can also find special garden paints that are specifically designed taking into account all factors - not to harm the tree by providing air exchange, and stay on the bark from autumn to spring. I will not list the names, so as not to create advertising and anti-advertising, go in, take an interest.
By the way, a separate line is a dispute about the need for whitewashing young seedlings. Some argue that they have a vulnerable young bark and that it is it that needs to be protected by whitewashing, and their opponents also base their arguments on the tenderness of the young bark and strongly advise against whitening it.Instead of whitewashing, you can use special garden or do-it-yourself bandages.
Is there an alternative to whitewashing?
Where is the way out? And the solution is very simple and logical, in my opinion. The same garden stores sell special garden bandages made of non-woven material. Being white, they will well reflect the sun's rays, not allowing the crust to warm up, but at the same time they let air through - the bark "breathes".
You say, expensive ... But you are not buying for one season. Well, you can safely replace the old (or new) agrofibre, cut into long narrow stripes (like bandages) and wrap them around the branches and the necessary branches of the tree. I have been using this method for several years now, with the same bands.
This protects not only from the formation of frost pits, but also from rodents (hares). The only thing that is required of you is to sometimes check that such a bandage covers the boom to the very ground. A simple thick paper or cardboard, burlap or fabric is suitable as a sun screen, such a protective layer is enough for one winter.
The main disadvantage is that during thaws, they can get wet and need to be removed and dried. In extreme cases, from the south side to the stem you can lean against a wide board, which will cover from sunlight.
In general, there are many options. And now that we have understood why we need whitewashing in the garden, it’s easier for us to make the right choice.