New growth will indicate extent of damage


We are getting close to the right time for pruning grapes. This next Saturday from 9 a.m. to noon is a class on pruning grapes at the orchard in North Las Vegas. This class will help you get started on the right path toward good grape production no matter if they are trellised or climbing an arbor.

Q. Our lemon tree shows damage after our recent very cold spell. Some of the leaves are dry and dropping. Is there anything we can do to assist the tree?

A. The damage can take several different stages. The degree of damage depends on the lowest temperature reached, the amount of time at this temperature and the source and condition of the plant.

The first stage is slightly below its tolerant range and results in leaf damage and other soft tissue death while the stems remain relatively undamaged.

The second stage is at temperatures slightly lower or held for a longer period of time. This results in leaf damage or leaf drop and death of smaller stems.

The third stage is complete death of the limbs and trunk back to the rootstock. The rootstock is normally a very hardy citrus grafted on to the more tender citrus.

In this third stage, the more valued lemon portion of the tree completely dies but leaves behind the more cold-tolerant rootstock. When temperatures warm, the rootstock will sucker into a totally new, but different, citrus tree.

You can get some idea now by bending some branches and see if they are supple and bend or if they snap off. But you will not really know the extent of the damage until you see new growth in a month or so.

Once you see where the new growth is coming from you can make a decision to keep the tree or remove it and start all over. If you have suckering from the limbs then you might want to prune it back and let it regrow.

If suckers just come from the roots then it would be wise to remove it.

Q. I have a loquat tree that is a few years old. I let it grow without any pruning so far. I did notice one of the branches growing from beneath what appears to be a graft union. Normally I remove any growth from below the graft as I do on my other fruit trees. That particular branch has new growth just starting. I was hoping this branch would give me the balance I needed since it was growing outward where there is an open space. Not sure if I should cut growth below the graft from a loquat tree.

A. From the picture you sent to me I can see this sucker is coming from the rootstock. Loquat is normally grafted on to a rootstock that is either not a loquat or inferior in fruit quality to the one you purchased. This sucker must be removed. Even if you could keep it, its attachment to the trunk is weak and will split from the tree when the limb gets heavier from fruit or size.

Loquats do nicely here and have some great fruit. Try to keep it out of late afternoon sun and don’t prune it too much so that the canopy is open. It will sunburn and you will have borers in the tree.

Bob Morris is a horticulture expert living in Las Vegas and professor emeritus for the University of Nevada. Visit his blog at xtremehorticulture.blogspot.com. Send questions to Extremehort@aol.com.

 

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