Imagine you own an orchard… how valuable would it be for you to be able to take your most productive fruit trees, clone them and make more with exactly the same characteristics and yield as the original? Until the advent of vegetative (or non-sexual) propagation this would have been but a dream, but now it’s pure commercial gold.
The likelihood is that if you have an apple tree in your garden it will have been created ‘naturally’ by the male cell of pollen from one tree fertilising the female cell of another, forming a fruit which contains a seed which when it falls to the ground will form another tree. This all sounds beautifully natural, but the problem with this is that the resulting tree has the genetic make-up of both the other trees so will grow unpredictably and its yield of apples will be just as random.
Not a problem for the average homeowner, unless you’re a massive fan of apple pies and need a predictable yield to satisfy your insatiable demand for the most important ingredient. For the orchard owner, however, this means their livelihood is left to chance, which is not so good.
This issue was solved by vegetative propagation – the ability to ‘clone’ a high-yield tree – to simply make another one with the same yield characteristics time after time after time.
How vegetative propagation works
Propagating a tree non-sexually can be achieved by taking a cutting and simply planting it. It will grow roots and produce an entirely new tree with the same characteristics as the old one, but it is slow and it’s risky as infection and pests could impact on whether a new tree grows at all.
Layering involves low-lying branches which can be bent down to the ground. A portion of the branch is buried with a few inches of leafy tip protruding. The buried portion will grow roots and has a greater chance of surviving as it is still receiving nutrients from the parent tree. Only once the new root system is strong enough will the link to the parent tree be severed.
Air layering is similar. A branch is wounded and then surrounded in moist moss in a plastic bag tied shut. New roots will grow from the wound and be fed with the nutrients they need directly from the parent tree until they are strong enough for the stem to be cut and planted.
However, grafting is the most popular method for propagating fruit trees. This is where you take a shoot cutting from a high-yield tree and join it physically to the rootstock of another related species of tree chosen for its beneficial complementary characteristics – fast growth, hardiness, etc. To join the two you need to ensure that there is firm contact between them at the layer below the bark, so some delicate surgery is required to remove the top crusty layer without harming either of them. They will then bond with one another and grow together as one, taking on a blend of both of their positive characteristics.
There are many ways in which trees can be propagated to create hundreds or even thousands of identical genetic copies of your best trees, but that’s a story for another time.
If you’d like to find out more about propagation or you’re happy with one or two apple trees in your garden yielding enough for the odd pie in the summertime and you’re looking for someone to help you keep them healthy long into the future, contact us on 0208 292 8992. We’re always happy to pop round or to help with a little advice or assistance.
