Wednesday, May 28, 2014

Pecan grafts breaking bud

   Its been about 3 weeks since I grafted pecan trees in my orchard. Look carefully at the photo at right and you'll notice that the buds on the scion have broken and are about one-inch green. Below the graft union is a profusion of trunk sprouts, producing leaves with the characteristically red tinge of a seedling rootstock. You should also note how the trunk sprouts got a head start on the scion sprouts in terms of growth.  When I applied the graft, buds on the scion were fully dormant. In contrast, buds on the trunk had already acclimated to spring time temperatures and were primed to go as soon I cut the top and placed the graft.
   To focus all the tree's energy into growing the buds on the scion, I pruned all the trunk sprouts off this tree. I like to complete this simple task as soon as I see new growth on the scion.  I have seen cases where trunk sprouts were not pruned off during the first summer after grafting and those sprouts eventually out-grew and shaded-out the scion. Lost in the deep shade of trunk suckers, a sprouted scion will actually die from lack of sunlight.
   The lesson here is to check your grafts early and often. And don't forget to always carry a pair of pruning shears.
    The photo at right shows a little larger tree with another graft I made this spring. The graft has sprouted but the side limbs I left below the graft have grown even faster. I left these lowers limbs on the tree to provide leaf area to support the root system but you can already see that these side shoots have turned to grow upwards and are competing with the graft for sunlight. I don't want to remove all the leaves below the graft union but I need to slow down the growth of these lower limbs. 
   The photo at right shows the same tree after I made several pruning cuts. First, I pruned off all but two branches below the graft. Second, I  removed all upward growing shoots from those two branches. And finally, I pinched back the terminals of edge side branch making sure to prune to an outward growing bud. Now my graft is back in full sun and ready to take off. I'll be back in a couple of weeks with some plastic tape to tie the scion's new growth to my bird perch. Oh, how I would hate to see a successful graft blow out in the wind!