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Four-flap Grafting of Pecans
Guide H-634 PH6-400
Esteban Herrera, Extension Horticulturist 
The four-flap is a simple grafting procedure that does not require sophisticated 
materials. Nursery managers, commercial growers, and homeowners can use this 
grafting method efficiently. Because necessary cuts and "fits" of the four-flap 
graft are not as precise as most other pecan propagation methods, it is a good 
method for beginners. In the arid West, the four-flap graft seems to be a more 
sure propagation method than patch budding, expecially if an attempt is made to 
force the buds into growth the first year.
The four-flap graft is successful because more cambium contact is made between 
the scion and the stock than with any other grafting procedure. The cambium is a 
green thin layer of cells located between the bark and wood, and is capable of 
dividing and forming new cells. The cambium contact between scion and stock is 
necessary for callus formation and a successful graft union.
The biggest advantage of using the four-flap is the ability to graft small 
seedlings. Although the graft works best if the graftwood (scion) and stock are 
the same size, the graft can be made with scions 25% larger or smaller than the 
stock. Optimum stock (rootstock) and variety size for grafting is 3/8-1" 
diameter.
COLLECTING AND STORING SCION WOOD
Grafting is often unsuccessful because graft-wood is not collected and stored 
properly. Desired varieties should be collected while the wood is dormant, in 
January or February in New Mexico.
  Young trees produce vigorous growth and are generally excellent sources of 
  scion wood. Do not collect scion wood that is 2-3 years old; for best results, 
  collect wood from the previous season's growth. 
  Collect scion wood from disease-free trees. 
  Select one-year-old wood 1/2-1" diameter (or the thickness needed). 
  Cut the scion wood into 6-8" sticks. 
  Wax both ends, using either paraffin or wax to prevent drying out. 
  Tie the sticks in bundles of about 25 each. 
  Identify each variety with a tag or by some other method. 
  Wrap scions in a wet newspaper or paper towels, then put into a plastic bag 
  and seal. Store in the hydrocooler of a refrigerator until it is time to 
  graft. Do not store graftwood in a freezer. 
TIME TO GRAFT
Grafting may be started when buds begin breaking and the bark slips freely (from 
April to August in New Mexico). Grafting may be continued for several weeks. The 
stock of grafts that fail may be cut back again after about a month, and a new 
graft put into place.
Procedure
  At a point where the stock seedling is straight and is about the size of the 
  graftwood, cut the stock straight across with sharp pruning shears at the 
  point where you want to make the graft. The stock should be about the same 
  size as the graftwood. Place a small rubber band on the stock to be used later 
  (1). 
  Make four vertical cuts 2-3" long and equally spaced (quartered) around the 
  circumference of the stock. Make the cuts through the bark only (2). 
  Choose a smooth, straight scion variety stick with the proper diameter. Cut to 
  about 6" in length with two or three buds remaining above the graft point. 
  With a sharp knife, cut the scion on four sides, starting the cut about 2" 
  from the bottom end (3). Make the cut through the bark only. The end view will 
  be square (4). NOTE: Many times only three cuts can be made due to the size of 
  the graftwood. This is acceptable, but it is best to have four cuts if 
  possible. When grafting a considerable amount of seedlings, it is better to 
  use a device available in the market that can make the four cuts (or three if 
  preferred) mechanically. This gadget will make the cuts simultaneously at the 
  right depth and the right length (5). 
  Pull the four flaps of bark down on the stock like a banana, exposing 2-3" of 
  white wood. Try not to touch the inner surfaces of these flaps (6). 
  With sharp pruning shears, cut and remove the exposed wood (plug). Be careful 
  not to cut or damage the four flaps (7). 
  Insert the prepared end of the scion squarely against the stock (8). Holding 
  it upright, pull the four flaps in place to cover the four cut surfaces on the 
  scion (9). Pull the rubber band up to secure the four flaps to aid in wrapping 
  (10). 
  Wrap the cut areas with grafting tape. Overlap each wrap only enough to 
  provide a complete seal. As you wrap, move the rubber band up the scion and 
  remove it (11). 
  Cover the tape with a piece of regular household aluminum foil, shiny side out 
  (12). Seal the top of the scion with a drop of white wood glue or shellac. 
  Slip a pint- or quart-size polyethylene bag down over the stock and tie with 
  soft string or plain vinyl tape just below the foil on the stock (13). 
  Covering the entire scion at this time may improve the chances for grafting 
  survival. You can use rubber bands, budding strips, string, masking tape, or 
  other tapes to secure the polyethylene bag in place. 
  When the buds on the scion begin to grow, cut the corner from the plastic bag 
  and slip it down and tie the scion approximately 1" above the foil and to the 
  stock 1 or 2" below the foil (14). 
*(Diagrams 1-15 are not available in HTML format. Please see the PDF file or 
contact NMSU Agricultural Communications for a hard copy.)
AFTERCARE
Keep growth on the stock in check throughout the first summer by removing the 
growing tips. This will cause a bushy trunk to develop, resulting in increased 
tree diameter and overall vigor. Stock growth can be used to regulate the graft 
growth rate. If the graft is growing slowly, remove most of the lateral growth 
on the stock. Should the graft make excessive growth that may cause the 
graftwood to break, allow the stock growth to remain longer. Normally, all 
growth on the stock below the desired height of the bottom limb is removed in 
two or three years.
After the graft has made about a foot of growth, cut down the side of the bag 
and remove it. Unwrap the foil and either remove the masking tape or cut it 
carefully in several places so the tape can expand without girdling the graft. 
Wrap the plastic around the graft union again, wrap the foil over the outside of 
the plastic, and tie loosely. This will continue to protect the growing graft, 
yet allow it to expand. Remove the foil and bag the following winter.
It is a good practice to tie a stick to the stock in two places below the graft 
to act as a stake for the growing graft. Tying the graft to this stake during 
the first season will make the graft main shoot grow straight and also keep the 
wind from blowing it off (15).
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and educator. NMSU and the U.S. Department of Agriculture cooperating.


Written: October 1993
Last Modified: March 1996
Placed on Server: March 7, 1996

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