Friday, May 30, 2014

Checking last year's grafts

     Last winter was rough on new grafts. Like area many growers, I've discovered that some grafts made in 2013 were  completely dead all the way down below the graft union. Other grafts looked perfectly OK and were sprouting new shoots. The most interesting part of part about graft winter kill this year is that it had nothing to do with choice of scion cultivar.  In fact, I can find no logical reason why some grafts died over the winter whiles other thrived.
    The photo above shows two Kanza grafts made in the same field just 100 feet apart. The graft on the left is completely dead. You can see where I had tied the graft's new growth to a bamboo stake with blue fagging tape last summer. Now, the tree is pushing out trunk sprouts below the graft union in an effort to grow a new top. Note the reddish color of the foliage. This tells me that all new shoots are coming from the seedling rootstock. I'll let this tree grow out this year and place another Kanza scion on the tree in 2015.
   The healthy tree (above, right) has already developed numerous new Kanza shoots. The only problem is that this tree has developed a 'lolly-pop' appearance--all the new shoots are clustered at the top of last summers new growth. This growth pattern is common for open grown pecan trees and is one of the major causes of poor tree structure. During this time of year I like to practice a little directive pruning and follow the 2-foot rule for tree training.

    The photo at right shows before and after views of the upper portion of last year's healthy graft.  There were at least eight new shoots growing to form the 'lolly-pop' at the top of this tree. My first priority was to identify the one vigorous shoot that would become my central leader. Next I removed all other lateral shoots within 2 feet of the top of my chosen leader.  This left me with a couple of lateral shoots at the base of the 'lolly-pop'. I then pinched out the growing points of the two lateral branches to slow their growth and help focus more  of the tree's energy on the central leader.
    Pruning out most of the 'lolly-pop' will also help stimulate growth from lateral buds further down the stem. In a couple of weeks, I should see buds breaking all along the trunk in areas that currently look bare. In training a young tree, my aim is to develop a well balanced tree with lateral branches growing out at regular intervals all along the trunk.