Plant Doctor Archive

Dwarf apple enormous

WE bought a dwarf apple tree a couple of years ago, but so far it looks like it has a higher growth habit, having now reached close to 3m tall. The name tag identifies it as Sir Price. Perhaps it should be more aptly called Surprise. Can you shed any light on the matter?

YOUR variety is likely to be Sir Prize - probably a spelling mistake on the label.

All apple trees you buy are grafted plants and the vigour as well as eventual size of the tree is largely controlled by what rootstock the named variety is grafted on to. So, for example, you could buy a Sir Prize tree on a dwarfing rootstock (such as M9) which will probably grow slowly to 2-3m. Or you could buy Sir Prize grafted on to a semi-dwarfing rootstock (such as MM106) which would grow more vigorously and probably end up 4m or more high.

Other factors, like soil conditions and local climate, will also make a difference, but it sounds to me as if your Sir Prize is grafted on to a fairly vigorous rootstock rather than a dwarfing one.

One thing you could do in an attempt to restrict growth is cut back long shoots in mid-summer rather than leave them to the normal pruning time of winter. You can also reduce vigour by tying shoots down so they spread out more horizontally rather than leaving them to head for the sky. This slows growth and encourages better fruiting on overly vigorous trees.

Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.