Dealing with Rootstock Suckers and Shoots

Reader Michelle wrote: “My nashi tree suddenly turned into a 6-metre-plus monster and the root stock appears to have taken over completely. This season it only had tiny cherry-sized hard brown inedible nashi fruit instead of its normal bountiful harvest of yellow nashi fruit.”

Michelle wanted some advice on how to manage her nashi tree. It was neglected and the rootstock had begun to take over.

The desired nashi variety is circled in blue. The rest of the tree has grown from the rootstock.

“Is there any way I can salvage my nashi fruit tree so it produces the desired nashi fruit again and stops the root stock from growing rampantly?” she wrote. “It has only ever produced the desired nashi fruit on one big branch, but it has always been bountiful on that branch. It would also be nice to get my view of the Dandenong Ranges back again as the monster tree is blocking it out completely.”

Essentially, Michelle will need to make some drastic cuts and remove the branches that have shot from the rootstock.

In this picture, you can tell the difference between the nashi and the D6 Pyrus callyerana rootstock by the pattern of the bark. The nashi is smooth and the D6 callyerana is cracked.

Removing the branches that have grown from the rootstock will have two main consequences:

1. Almost two-thirds of the tree will need to be removed. The tree is going to create a huge amount of vigorous foliage growth in response. Going forward it will be difficult to keep the fruit tree small.

2. It is going to be difficult to cut the rootstock branches off cleanly. It is likely they will continue to send out side shoots forever. This means Michelle will need to be extra vigilant to keep it from happening again.

This sort of problem growth from the rootstock can occur with any grafted fruit tree. It’s quite common in citrus, cherries and many other stone fruit. As always, prevention is better than cure. Here’s what to look for in your fruit trees and how to fix it before it becomes a major, chronic issue for your fruit tree.

A stick in time saves nine

Spotting emerging rootstock shoots early and removing them can make life much easier. Once the branches start to take hold, they can create a bigger issue. Often rootstock varieties are quite vigorous and they’ll quickly outgrow the desired variety of tree that’s been grafted on top.

You can see on my young orange tree that there are some shoots emerging from the rootstock.

Rootstock shoots often look different from the rest of the tree. I can tell that the shoots in the image above are from the rootstock because their leaf shape is completely different. The rootstock is trifoliata, which in Latin means “three lobed leaf”. Some rootstocks will be much thornier than the rest of the tree.

Sometimes – in plums, for example – the emerging rootstock shoots have different coloured foliage from the rest of the tree.

When you see rootstock shoots emerging you can easily remove them by rubbing them off cleanly with your thumb. This method doesn’t allow the same bud to re-shoot (more on this in a minute).

What should I do if things have already grown a bit out of hand?