Plant Doctor Archive

Strange avocado

THERE'S an old avocado tree with a forked trunk on our property which behaves very strangely. It's in a sheltered spot, is healthy and grows well, but one side of the tree yields lots of fruit, with nothing from the other side. It's the same side every year that fruits - the right-hand trunk in the photo. Can you help?

AVOCADOS are propagated by grafting a piece of a good cropping variety, such as 'Hass' or 'Feurte', onto a rootstock (usually an avocado grown from seed). It looks as if, during the early years of your tree's growth, a shoot grew from below the graft (the left trunk in your photo). This shoot should have been cut off while it was still very small to allow the grafted part (the right trunk in the photo) to grow and form the upper part of the tree.

It's too late to cut it off now, as removing a branch this large would not only seriously affect its health but would also ruin the look and shape of the tree.

I suggest you prune out branches on the "unbearing" side each year to encourage growth on the other side, otherwise the shoot from the rootstock may eventually dominate with the result you'll get fewer fruit each year.

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