Successful Collection of Pecan Propagation Wood

Many new orchards in Louisiana are initially planted using ungrafted seedling trees purchased from the state or local nursery. However, seedling trees are slow to begin bearing and generally produce nuts which vary in size and quality. To correct these deficiencies, vegetative propagation techniques (budding and grafting) are used to produce trees yielding nuts with uniform characteristics. Successful budding or grafting in the spring is dependent not only on the proper selection and collection of scionwood but also on knowing how to properly store the wood for later use. Selection of weak/damaged graftwood and/or improper storage of graftwood will generally result in a low survival rate or “poor take.”

January and February is the right time to collect graftwood for whip, four-flap (banana) and inlay-bark grafts. Parent trees should be vigorous and free of insect, disease or environmental damage. It is a good idea to select trees in the summer to be sure that the trees are true to type for the variety of pecan you want to collect and propagate. Ideal scion sticks are smooth and straight and are usually between ¼ and ⅝ inch in diameter, but larger and smaller wood can be used. Handle wood carefully when collecting to minimize damage to the buds. Suitable budwood or graftwood should have 3-4 buds at each leaf node (primary, secondary and tertiary buds).The smaller tertiary buds serve as insurance if the primary or secondary buds are lost or damaged. For graftwood, collect fast-growing, one-year-old, straight shoots from the tops of young trees. If you do not have access to young trees, older trees which were pruned heavily the previous season will have fast-growing shoots at the point where large cuts were made. Or you can cut back or dehorn trees now to produce graftwood for next year. If neither of these sources is available, less-vigorous side limbs or two-year-old wood can be used. But this wood will generally result in a lower success rate, and it is more difficult to accurately cut and use for most grafting procedures.

Budwood to be used for patch-budding shouldn’t be collected until early or mid-March. It is necessary to wait later for this wood since the bark must be slipping for use in patch-budding pecans. Budwood is often larger than wood collected for grafting – up to an inch in diameter. It is stored the same as graftwood but is treated differently prior to use. Budwood, still in its storage container, is placed at room temperature (75-85 ºF) for 4 to 7 days to “season” the wood. Use the budwood as soon as possible after the bark begins to slip. Budwood should be labeled and stored separately from graftwood because of the difficulty of “seasoning” January-cut wood for budding.

The collected graftwood or budwood should be cut into 6-, 12- or 18-inch sticks, which will yield one, two or three graft sticks. The collected shoots should never be allowed to dry out before processing. The ends of the scionwood are generally sealed with orange shellac, paraffin or grafting wax. No matter what you seal the ends with or if you choose to not seal them at all, it is crucial that the wood be placed into polyethylene bags as soon as possible. Moist (not wet) paper towels, newspaper, wood shavings or sphagnum peat moss may be used as packing to keep the wood from drying out in storage. Make sure all graftwood and budwood are labeled by variety, source and date collected. While labeling the exterior of the storage container is usually adequate, many collectors will also cut a 1-to-2-inch section of bark off of one of the scion sticks to be stored and write on the light-colored xylem wood with a lead pencil as a back-up label in case the exterior label is lost or becomes illegible. Graftwood should be refrigerated at 35-40º F until it is to be used, but be sure the wood is not exposed to freezing temperature (the back portion of some refrigerators when set to near 40 ºF may actually be below 32º F). Remove only the amount of wood you will need, and carry it to the orchard in an ice chest. Never allow the wood to dry out from the time the shoots are initially cut until the graft is completed.