Wednesday, May 16, 2018

Decisions in making a 3-flap graft

    Every morning I've been grafting the volunteer pecan seedlings that have sprouted on my farm. Since these "pasture" pecan trees have been mowed over at least one time in the past, most of these seedling trees have multiple stems. I prime example is pictured at right.

    In grafting this tree, I started by cutting off the small spindly shoot below ground level (photo at left).

   The two remaining shoots were perfect candidates for making a 3-flap graft. I selected the largest diameter scion I had in my cooler and held it up to each shoot to judge the locations were scion and stock were roughly the same diameter. The stem on the left was slightly larger (in diameter) that the stem on the right. I soon discovered that a 3-flap graft applied to the left-hand shoot would sit much higher up the stem than one placed on the right-hand shoot (photo above).  

   Given a choice, I have found that cutting off more of the stock tree increases scion growth rate once the scion calluses.  I decided to place my graft on the right-hand shoot and prune off the left-hand shoot (photo at right). Again, I cut off the stem as low as possible.
  You might be wondering why I didn't graft both stems. I find that wrapping the graft becomes a problem when you have another stem in the way. It hard to concentrate on pulling the grafting tape hard enough to compress the bark flaps against the scion when you keep bumping into another pecan shoot.
    Once I cut out the competing stem, I held up my scion to find just the right spot to place the graft (photo at left).

   I always look to avoid making a 3-flap graft on a stem with a pronounced "dog-leg". In the photo above, the yellow arrow points to the spot I plan on cutting the stock tree.  Above the arrow, the stem zigs and zags. However, below the arrow the stem is nice and straight. I always cut the stock tree off at a location that maximizes the length of straight stem.  It is so much easier to create three, even-sized flaps when working with straight wood.

    Once I choose the spot to make a graft, the rest of the grafting procedure was completed using the typical 3-flap grafting method. The photo at right shows the completed graft along with an attached bamboo stake that I'll use for training the scion this summer.