What Is Rootstock?
Rootstocks are the roots of trees which have been cut off from their parent stock. They may be young or old, they may be rooted or not rooted at all. Most often, these roots are planted into soil and grow with it. However, some trees do not need such a support system and can thrive without it (e.g., acacia).
The most common type of rootstock is that which was taken from dead trees. These roots were usually cut off at the trunk and then brought to a place where they could be cultivated. Such roots would normally be grown in pots or containers, but since they had no support, they grew very slowly. Eventually, these roots died out completely and needed to be replaced with new ones. Thus, a new tree was born!
Another type of rootstock is that which comes from other plants. Usually, these roots are grown in soil and grow faster than those from dead trees. In fact, when grown in soil, they can even outgrow the pot they’re growing in! When grown like this, they require less maintenance because there’s no need to water them. Plants grown from rootstocks are called grafted trees.
Grafted trees are often those which fruit abundantly or bear flowers for a very long time.
Why Do We Use Rootstock for Trees?
A rootstock is like a plant’s support system. Normally, when you see a fruit tree in the wild, it looks very sturdy and strong. However, this is an illusion and actually, the tree is quite weak on the inside. The majority of the structure is hollow and filled with nothing except air! This makes it very fragile. When you plant an isolated tree in the middle of nowhere, it becomes very susceptible to winds and falling over. Grafting a rootstock onto the bottom of the tree allows it to become much stronger.
The root system of a fruit tree extends several meters all around and below the original roots. When you take a rootstock from another fruit tree with a well-established root system, you are able to give the new tree a head start in life. Instead of having to wait several years for the new tree to develop its own roots (which might never reach as far as they need to), the new tree can immediately use the established root system of the old tree. In this way, a large and strong root system can be grown within just a few years.
When you’re growing a new garden in a place where nothing has ever grown before, it’s important to first prepare the soil. There are many ways of doing this, but without a good way of anchoring the soil as it’s being prepared, it can all be lost to erosion. One way of doing this is to dig a deep hole and carefully lower a rootstock into it. After the hole has been filled in with mud, you can then carefully water the newly planted area.
Sources & references used in this article:
Breeding apple rootstocks by JN Cummins, HS Aldwinckle – Plant breeding reviews, 1983 – Springer
Understanding how rootstocks dwarf fruit trees by C Atkinson, M Else – Compact Fruit Tree, 2001 – researchgate.net
Rootstock-scion relationships in hardiness of deciduous fruit trees. by MN Westwood – Horticultural Science, 1970 – cabdirect.org
Rootstock-regulated gene expression patterns in apple tree scions by PJ Jensen, I Makalowska, N Altman, G Fazio… – Tree Genetics & …, 2010 – Springer