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Dwarf crabapple tree reverting #877018

Asked July 12, 2024, 3:44 PM EDT

My beautiful dwarf crabapple tree Tina (grafted) dwarf version of Sargent crab apple is growing much larger branches and leaves as of two months ago. I had been concerned about what I thought was canker sore on the trunk, but was told by the nursery where I bought it three years ago that it was just from the grafting. At that time I had not noticed the much larger leaves growing on the new branches. How can I stop this growing? The tree is planted in a space that is only big enough for a dwarf tree.

Bennington County Vermont

Expert Response

Hello Mia

If your dwarf crabapple tree is growing larger branches and leaves after three years, it could be due to a few factors:
Possible Causes

Rootstock Influence: Dwarf trees are often grafted onto rootstock that controls their size. If the tree is reverting to the characteristics of the rootstock or if the graft union is failing, the tree might start to exhibit more vigorous growth.

Environmental Conditions: Favorable growing conditions, such as optimal soil, water, and nutrient levels, can sometimes result in more vigorous growth than expected.

Pruning Practices: Inadequate pruning can lead to larger, more vigorous branches. Regular pruning helps maintain the tree's desired size and shape.


Thank you

Sean






Sean Warner, UVM Extension Master Gardener Volunteer Replied July 14, 2024, 3:04 PM EDT
Thank you Sean.  Well there has certainly been optimal growing conditions this summer.  All plants and flowers seem more robust and prolific than is usual in this area.  I don’t mean just in my garden but everywhere.
As far as the pruning, do I have to wait or can I do any pruning now or will that just make it worse?
How can I tell if it is a failed grafting?  The tree has looked perfect for 3 years, but I have done very little pruning to it.

Thanks, 
Mia

Sent from my iPad

On Jul 14, 2024, at 3:04 PM, Ask Extension <<personal data hidden>> wrote:


The Question Asker Replied July 14, 2024, 4:05 PM EDT

Good morning Mia

Pruning should be done in late winter/early spring. Do it before the tree 'wakes' for the spring. It will easily heal over those pruned areas.

Check to see if there are any suckers coming from below the graft. These would be from the rootstock and would show the graft is failing. I would also recommend looking for an arborist. They can give you better details on what to look for.


Thank you

Sean


Sean Warner, UVM Extension Master Gardener Volunteer Replied July 16, 2024, 5:36 AM EDT

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