Own-root apple trees

We are offering a small quantity of apple trees grown on their own roots, without the use of a rootstock, for delivery in autumn 2012.

What is an "own-root" fruit tree?

The vast majority of fruit trees produced world-wide are propagated on rootstocks. The fruit tree therefore consists of two parts, the rootstock which is mostly below ground, and the scion (fruiting variety) which is the main part of the tree visible above ground. If you look carefully on a young tree you can see the kink in the stem just above the ground where the main tree has been grafted on to the rootstock. Fruit trees are therefore very different in this respect from other trees - the typical oak tree growing in a field will have grown from seed, on its own roots.

Budded, Grafted, Own-roots

The photograph shows from left to right:

  • A 1-year bud-grafted apple tree. You can clearly see where the rootstock was "headed" to allow the grafted bud to grow away. After a few years the bud will grow right over the top of the rootstock.
  • A 1-year bench-grafted apple tree. The grafting wax is still visible, and the stub of the rootstock can be discerned in the centre of the tree (the graft slants from top right to bottom left in the centre of the stem).
  • A 2-year own-root plum tree. Note how there is no graft union on the own-root tree.

The technique of using rootstocks for growing fruit trees has been known for hundreds of years, but it was not until the early 20th century that standardised virus-free rootstocks became available, at which point the use of rootstocks quickly became the standard way of producing fruit trees. Before that time, the propagation of fruit trees was more haphazard, with a good number being grown simply on their own roots.

Thus own-root fruit trees are in some senses a more "natural" way of growing fruit trees. There has been a resurgence in interest in own-root fruit trees, partly as a result of the work of English apple breeder Hugh Ermen in the late 20th century.

Advantages and disadvantages of own-root fruit trees

Hugh was a great believer in the benefits of own-root fruit trees. He argued, with some justification, that the artificial joining of two different types of tree (the rootstock and the scion) created a degree of incompatibility. By growing the fruit tree on its own roots this incompatibility was removed and as a result the tree would be more healthy, live longer, and the fruit would have more flavour.

Unfortunately Hugh's work has not been continued so the true extent of these benefits is not really known. It is fair to say that an own-root tree is more natural than a conventionally-propagated fruit tree.

However it is important to be clear about the disadvantages of own-root trees. There are two main issues:

Firstly, one of the main benefits of a rootstock is that it controls the height and size of the tree. Own-root trees do not have this control and if no alternative measures are taken, will grow quite large over time. As a guide, they are likely to achieve a similar size to a conventional tree on the MM106 rootstock. However the size of any given own-root tree varies more widely than a tree propagated on a rootstock and it is difficult to predict the mature size with the same degree of accuracy.

Secondly, own-root trees take longer to grow and will not start fruiting as early in the life of the tree as the same variety grown on a rootstock. It would be un-wise to expect any fruit before the tree is perhaps 5 years old. This is because most rootstocks, especially the more dwarfing ones, are precocious - they encourage the tree to reach maturity and start fruiting earlier than it otherwise would.

For these reasons it is unlikely that own-root trees would ever be used commercially, but in a garden situation they can make an interesting alternative to conventionally-propagated trees for the enthusiast.

It is also possible to counter the drawbacks described above, through careful choice of variety. The problem of excessive tree size can be addressed by selecting varieties that are naturally of low-vigour. Similarly, the problem of having to wait many years for the own-root tree to start producing fruit can be addressed by selecting varieties that are naturally precocious and like to fruit early in their lives.

How are own-root trees propagated?

This is the key question. Unlike oak trees, many fruit tree species, particularly apples, do not grow true from seed. In other words, if you plant a pip from a Discovery apple tree, the resulting tree will not be a Discovery - it will be a cross between its mother (Discovery), and whatever other apple tree variety pollinated it (almost certainly not another Discovery tree). Whilst this makes it easy to raise new varieties, it is a problem if you want an apple tree of a particular variety growing on its own roots.

Since growing from seed is therefore not possible, Hugh Ermen developed several techniques for propagating own-root trees. One of the most successful involves grafting a piece of root of the desired apple variety on to a conventional M27 rootstock, which acts as a temporary "nurse root" to get the own-root tree started. The resulting combination is then planted out in the nursery, but much deeper than usual. The M27 rootstock provides the initial growth, but the grafted root soon takes over and because it is naturally very vigorous, rapidly out-competes the M27 rootstock which eventually dies away. The tree then grows away vigorously on its own roots.

It is relatively easy to tell if a young tree has been grown on its own roots, because there will be no kink where the rootstock would join the scion as in a conventional fruit tree. Instead there will be a continuous smooth stem from the roots up.

Apple trees for sale grown on their own roots

We are offering the following apple trees grown on their own roots, for delivery in autumn 2012. These varieties have been chosen as being particularly suitable for growing on their own roots. They are naturally good croppers, not too vigorous (so they won't get too big) and naturally precocious so that you will not have to wait too many years before getting some apples. Some of them are varieties that were developed by Hugh Ermen himself.

Trees can be ordered now, but will not be delivered until autumn 2012. You will not be asked to pay until nearer the time.



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