Thursday, June 29, 2017

Time for pecan graft maintenance

    Today I was working on trimming and training this year's new grafts. The photo at right shows a young bark graft that has developed a nice strong shoot from the scion. However, this tree still needs some attention.
    Three weeks ago I forced new growth from the scion by pruning off all bark sprouts growing below the graft union. But now, you can see new bark sprouts have formed (note leaves with reddish coloration).
   So my first step in pruning this tree was to remove all stump sprouts (photo at left). Now, you can clearly see the graft union. My next step is to prune the scion's new growth down to one shoot.
    The photo at right is a close-up of the graft union. As you can see the scion has developed three shoots. The uppermost shoot (labeled A) is hardly sprouted out. I will remove this shoot by cutting the scion at the point marked by the red line. Next, I will remove the secondary shoot (labeled B) so that all the tree's energy will be directed to the much larger primary shoot that will become my new central leader.
    To prevent the grafting tape from girdling the scion, I'll remove the tape (labeled C) but leave the rest of the graft wraps on the tree at this time.

    After pruning the scion I'm left with a nice single stemmed tree (photo at left).  The slight crook in the stem will eventually disappear  as the new shoot grows in diameter. Before leaving this tree I always inspect the new shoot for the formation of stalked buds.
     I found  a stalked bud at nearly every leaf axil. In the photo at right, I pointed out all the stalked buds (orange arrows) on just a portion of the scion's new shoot.  Starting at the base of the shoot, I use my fingers to grab each stalked bud and pull them off the shoot. On this tree, I found stalked buds at every leaf axil over the entire length of the shoot.
Once the stalked buds were removed, I used some blue engineer's flagging tape (any color will work) to secure the new shoot growth to my bamboo training stick (photo at left). Now that I've pruned the scion down to one shoot, I want to do everything possible to prevent the wind from snapping off the graft. My final step in protecting this graft was to replace the deer cage back over the tree to prevent browsing damage.
   In about 3 weeks, this tree will need more attention. I'll need to prune off any new stump sprouts, remove stalked buds that develop on new growth and tie the new shoot to the stake as the tree grows in height.