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A word often used in the description of fruit trees.
But what do people (and books) mean when they describe a variety as "vigorous"?
In my experience, when authors describe fruit trees, "vigorous" tends to mean a tree which eventually might get large, even if it is not fast-growing.
Quite often such trees are triploid and/or tip-bearers. In many cases, "medium vigour" triploids will still become very large trees as they age; larger than their accompanying diploid trees.
No doubt the triploids don't lose as much vigour when cropping begins because of the lower numbers of good seeds per fruit compared to diploids, resulting in less nutritional demands to produce fruit and hence better nutrient availability to the shoots resulting in more annual shoot growth.
As a consequence, I would expect triploids to be able to be allowed to crop heavily at an earlier age than diploids without as much risk of stopping the tree growth.
The tip-bearers, of course, tend to be trees which have to continue to grow new shoots on which to carry their crops at the tips in the following year.
Not to mention that pruning tip-bearers is a more complex task which, if done incorrectly, can result in no crop and all the energy which would have gone into fruit being vented out as very vigorous shoot growth.
But what do people (and books) mean when they describe a variety as "vigorous"?
In my experience, when authors describe fruit trees, "vigorous" tends to mean a tree which eventually might get large, even if it is not fast-growing.
Quite often such trees are triploid and/or tip-bearers. In many cases, "medium vigour" triploids will still become very large trees as they age; larger than their accompanying diploid trees.
No doubt the triploids don't lose as much vigour when cropping begins because of the lower numbers of good seeds per fruit compared to diploids, resulting in less nutritional demands to produce fruit and hence better nutrient availability to the shoots resulting in more annual shoot growth.
As a consequence, I would expect triploids to be able to be allowed to crop heavily at an earlier age than diploids without as much risk of stopping the tree growth.
The tip-bearers, of course, tend to be trees which have to continue to grow new shoots on which to carry their crops at the tips in the following year.
Not to mention that pruning tip-bearers is a more complex task which, if done incorrectly, can result in no crop and all the energy which would have gone into fruit being vented out as very vigorous shoot growth.
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