Grafting Pecan Trees in South Central PA, Part 2 of 3
Posted: April 17, 2012
This is the second of a series of three titled articles focusing on the 3-flap graft.
Who? Those who have previously obtained pecan seedlings in past years and have now raised the trees to ½ inches in diameter, that will be called “stock”.
What? Grafting desired varieties on stock that’s ready to receive them.
Where? At your site, in South Central Pennsylvania, or in nearly Maryland.
Why? To bring the tree into production in the next few years with pollination and climate compatible varieties. Otherwise we wait 15 years for nature to take its course plus gamble on pollination compatibility.
When? In mid-May 2012, in the early morning. My early morning success rate is as high as 90%. My afternoon success rate is 0.00%. There is a lesson there.
How? That is the gist of this article and pictures. More pictures and information are available at: http://www.centerforagroforestry.org/pubs/proppecbw.pdf
This article is based on 28 years of experience at my farm in Kansas and 3 years experience in Carroll Valley, Pennsylvania, plus a number of seminars given by Dr. William Reid, author of above referenced article.
First we need your stock tree, grown to ½ inch or larger, and scion, provided by me. The scion is a piece of limb 3/8 to 5/8 inches in diameter, 6 to 8 inches in length, taken from a bearing pecan branch. The scion will be harvested while dormant, in February.
Referring to the photos, top left, we match the scion size to the stock, and then clip the stock with sharp pruning shears. Then, top center we vertically slice the bark, 2 inches in length, at 3 points, 120 degrees apart. Why three? Because you will find that pecan buds line up 120 degrees apart. Then, top right, we peel the resulting 3 flaps of bark back about 2” exposing the woody portion of the stock, and clip at bottom of the cut.
We attach a couple of feet of grafting tape, provided by me, just below the flaps.
Referring to the bottom photos that show the scion, we cut the ends back about a quarter of an inch to remove dried wood, then make three 120 degree spaced cuts just under two inches to match the flaps on the stock, deep enough to expose the cambium. We then match the scion to the three flaps at the top of the stock. Now carefully, without touching the cambium, holding the flaps over the scion, match the cuts with the flaps. This will give cambium to cambium contact. The cambium is the material that supports sap transfer from the roots to the growth buds, and it’s vital to the success of the graft that they are in intimate contact.
Now we wind the grafting tape around the graft, tightly, overlapping half or two thirds until the cut edges previously made in the stock are contained.
Do to space limitations, only 6 of the 12 photos in the referenced article are shown, but from this point we add a plastic sandwich bag cover, seal it air tight with grafting tape, then wrap the graft with aluminum foil from the kitchen to avoid any ‘green house’ effect.
Attach, extending both above and below the scion, an 18 to 24 inch branch to both mechanically hold the graft in position while it grows together and discourage large birds, i.e., crows, hawks, etc. from landing on it and breaking it off.
The last step is to spread a drop of household glue on the top end of the scion to seal it. This will force the rising sap into the growth buds.
Later, every few weeks, the growth needs to be pruned back to avoid overgrowth and wind damage.
If you have seedling new stock ready to graft or want to plant seedlings this summer, please email me at Devlinw1@aol.com and I will schedule a visit for grafting. You can pick up the seedlings at my home in July or early August if you wish to start pecan seedlings.
Bill Devlin is a Penn State Extension Master Gardeners from Adams County. Penn State Cooperative Extension of Adams County is located at 670 Old Harrisburg Road, Suite 204, Gettysburg. Call 334-6271.