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Wednesday, February 27, 2019

Cutting pecan scionwood

     Folks often ask me when is the best time for cutting pecan scionwood. Yesterday, while cutting my own scions, the answer presented itself. A large flock of honking geese flew overhead on their way back north. It jogged my memory of previous years of scionwood collection and I realized that the spring migration of geese always coincides with the perfect time to cut scionwood.

   Earlier this week, we had some good weather for working outside and I cut scions for all the grafting I have planned for 2019. I started by attacking a young grafted tree that had grown a lot of strong vigorous shoots the previous season (photo at right). Most one-year-old shoots on this tree were 2 to 3 feet long.
     Looking at the top of the tree, I noticed that three shoots were competing to be the primary central leader (photo at left). In harvesting scions from this tree, I could not only get some great scions but I could train the tree back to a central leader.
    I cut almost every one-year-old shoot off this tree which yielded a good collection of twigs that could be cut into scions (photo at right). At this point in this young tree's life, I'm not concerned about cutting off all potential nut producing shoots. This tree is so small that any nut production at this stage would be minimal.

    I like to store my scionwood cut into pieces appropriate for making a single 3-flap or bark graft. When cutting the wood, I always make sure to pay attention to the location of buds near the top of the stick. I cut the wood about 1/2 inch above the upper-most bud, then make sure I have a second bud within the upper half of the stick (photo at left). I don't worry about buds on the lower half of the stick because they will be removed during the grafting process.

    While cutting up scions, I also look for stalked buds (photo at right). These type of buds do not prevent a graft from taking but they are a problem during scion storage. Stalked buds tend to puncture plastic storage bags increasing the risk of scion desiccation during refrigerated storage.
     You should note a strong secondary bud just below each stalked bud. I carefully snip off the stalked bud making sure not to injure the secondary bud (photo at left). Only after this detailed pruning is complete do I place the scion in a storage bag.

   
    A single long shoot can produce several scionwood pieces. The photo at right shows a typical one-year-old shoot harvested from a young tree.

    When cut into graft sized pieces, I was able to get six scions (photo at left). These sticks are arranged in the older they were cut from the shoot pictured above. The larger diameter scions are perfect for 3-flap grafts while the small diameter wood is better sized for bark grafting. I discarded the terminal piece.

 
 The photo above shows how I harvested the scionwood from a young tree. Note that I left a single shoot at the top of the tree to become a central leader. All other shoots were stubbed back. Next spring, this tree will sprout new shoots from two-year-old wood and fill out its canopy.

    I don't always butcher my trees to collect scionwood. Many times, I'll collect wood from the pruning cuts I make at this time of year. The tree pictured at right is a prime example. This tree has formed two central leaders connected by a narrow fork in the trunk. I should have spotted this problem a couple of years ago but I'll take this opportunity to correct the problem now and collect some scions.



     Just one cut with the chainsaw and I recreated a central leader tree (photo above). Yes, I see the branch fork at the very top of the tree. I didn't have my pole pruner on hand, so that cut will have to wait.

   Once I had the pruned-off portion of the tree on the ground, I  noted the numerous shoots that could be harvested for scions (photo at left). Again, young trees seem to produce nice long on-year-old shoots.

    With just one pruning cut, I was able to harvest a whole pile of scions (photo at right). Since the harvested scions range in diameter, I'll be able to find the perfect sized piece when it comes to matching scion to stock at grafting time. 
    I discussed proper scion storage in my previous post HERE.