Monday, February 26, 2018

Dormant pruning last year's bark grafts

    Finally, the sun came out and it was a great day to get outside.  I hopped into my UTV and drove down to the pecan grove to check on some of last year's bark grafts. The photo a right shows a Kanza graft that grew exceptionally well. The scion produced three strong shoots with the central leader growing over five feet in length in a single growing season.

   However, taking a closer look at the scion, just above the graft union, reveals that I've already got a tree with a narrow fork and a side limb that's growing way too close to the ground. So I grabbed my pruning shears and made a couple of much needed cuts.
    First, I removed the left side of the narrow fork. Then I pruned off the side limb growing out to the right (photo at right). This left me with a single central leader and a good shoot to develop into my main tree trunk.  After pruning, I moved down to the graft union and removed the plastic bag and aluminum foil from the tree.
    With the graft wraps removed, you can see that the graft union has callused over nicely. On the left side of the graft union you can still see the staples I used to attach the graft.   But notice the color of the bark that was once covered by the aluminum foil and plastic bag.  The chestnut brown color of the bark indicates that this bark is not used to being out in full sun and may be prone to sun-scald.
     At this point, I used some cheap latex paint to apply a sun block over the entire graft union (photo at right). I used white paint to mark the tree as being grafted to Kanza. By painting the graft unions, I can quickly see which trees are grafted and which cultivar is grafted on the tree. On my farm, white=Kanza, yellow=Lakota, green=Hark, etc.  It takes a little extra time and money to color code trees but its definitely worth it to help me keep tract of my grafting efforts. It easy to get lost in my pecan orchard because it is based on grafting volunteer seedlings that have popped up at random across the field. No nice straight rows to keep things in order.
   Once I replaced the deer cage over the tree, I noticed that the top of central leader had several small branches that had developed from stalked buds (photo at left).  All of these shoots would develop into narrow-angled branched with deep bark inclusions. So to prevent future problems with limb breakage, I pruned off each small shoot and any remaining stalked buds.
       After pruning the central leader, I was left with a single strong shoot (photo at right). When this tree starts to bud out this Spring, I'll need to return with my clippers to perform some directive pruning to help maintain good structure. Side shoots will  emerge this coming season and my new Kanza graft will start looking like a pecan tree.