Hardwood Stooling is the name given to a specific technique that is quite easy and can be used by home gardeners looking to propagate plants such as rhododendrons and fruit trees.
There are two important points to understand however.
First – Stoolling does NOT work on mature trees and shrubs of the size you buy from garden centers – those trees are already too large for stooling. See Air Layering instead.
Second – do understand that the plant you use to root will be the plant you get to grow. This might sound a bit strange but the majority of fruit trees on the market today are grafted trees.
The rootstock used acts to dwarf the tree and change its growing habits. The top of the tree is a full-sized apple (only dwarfed by the grafted-on root) The root controls the size of the tree.
This is important because while you can get a crop of apples from a “full dwarf” tree after 3 years and a semi-dwarf after 5-7 (give or take)
If you propagate from the top of that tree, and it’s not grafted to a dwarfing-root, you will have a full “standard” tree and you’re looking at 12 years to get a crop (again more or less).
So while you can get fruit trees using this system, you will get a full sized tree of your stooled plant and not a replica or dwarf tree. The way to get a dwarf tree is to graft a bit of the top onto a rootstock (grafting is not covered in this course).
Stooling and Air-layering involve taking a branch of a woody plant and encouraging it to form roots independently of the main root system.
Is normally considered a nursery practice because of the way the mother plant is treated.
Let’s use an apple tree as an example. (note this does NOT work on mature apple trees or those you buy from garden centers – those trees are already too large for stooling. See Air Layering)
The mother tree – a very young plant on it’s own roots – something in the height of 2-3 feet tall is cut down to one foot tall. The plant, because it is so young, will develop a large number of shoots. Do this in year one and allow the plant to overwinter
In year two, when these shoots have leafed out, the tree is mounded over with soil to cover the shoots but allowing the growing tip to remain exposed. (see diagram). More soil is added through the growing season until mid-summer and in the fall after the plant has dropped it’s leaves and gone dormant, the mound is carefully removed, the shoots with their roots are cut off the mother plant and the soil removed. In the spring, the mother plant will once again produce new shoots and the process is repeated.
This system produces a very high number of new plants and is used quite extensively in rootstock production on a commercial scale. It is seldom used in the home garden.
Because of the length of time to harvest and the economics of producing standard trees versus dwarf trees by grafting, this technique is not usually used for producing fruiting trees.
On a home scale, understand that this is not a casual method to obtain a new plant or two but rather one in which you are sacrificing the mother plant to produce any number of new plants.