Collecting scionwood properly can increase the success rate of grafting. This post will identify the type of wood you are looking for, and why scrutiny is important.
This first photo shows the final product, a length of new growth wood about a foot long (30.48cm).
Getting to this point is as follows:
- Get out there and collect, looking for good healthy material. Avoid any noticeable pathogenic organisms like cankers, fungal bodies, etc. We are after growth from last season only, anything older will likely result in failure. In the following photo, notice the ripples in the bark near the base of this scion which divides this past year’s growth from the previous year’s.
a. In terms of length, the longer the better. Thickness follows in suit with length generally, but with caliper you will want to look for sizes that accommodate your rootstock size.
b. The next (top) photo shows a nice branch with 12 inches of new growth. Often this wood is at the periphery, but with strongly pruned trees, candidates are abundant in all areas of the tree. Keep in mind some wood from very low down in seedling trees may be juvenile in nature and should be avoided. These “watersprouts” may take longer to bear, though in grafted trees, which is what we all generally are dealing with, this is less the case. The bottom image shows a poor choice of wood on the tree, having no useable wood at all. This branch has had its tip dieback in the growing season from insect damage, and side growth is composed of fruit spurs. Fruit spurs are not eligible for grafting, as they are less likely to result in shoot-like growth , and the possible blooming will drain the scion of moisture and nutrients (removing the blossoms has not been shown to negate the problem appreciably).
- Next are two examples of wood of poor choice: (ruler in photo is in inches)
a. The image on the top is a length only 2 inches long. Since buds on the distal end (toward the tip) are usually less developed, succulent or prone to cold injury, and since buds on the proximal end (toward the base) are usually small and tardy in growing. The section of wood here shows little choices remaining.
b. The lower example is shorter still, with spurs and spurlike growth without a useable amount of internodal space. The internode is simply the space between the buds, which becomes important in grafting because it is the area where the cut is made. The longer the cut, the more cambial contact is allowed for, and thus great chance for union to be made. (More on this point in the grafting posts).
This final image gives us an idea of the minimal caliper and the optimal internodal spacing. In this specimen an oblique cut of nearly an inch can be made for a whip graft. The buds are apparently healthy, without being so protruding as to break off during grafting or transport.
Finally, the timing of gathering will depend on the climate of the area. Here in the northeast of the US we are collecting during pruning time, which is generally from February through May. Ideally, collection like pruning should be attempted after the coldest days have passed but safely before growth has begun. A point to keep in mind is the closer you can time it to coincide with the actual grafting the better due to keeping things fresh. Although wood can be kept for many months under moist refrigeration, there is less to go awry when the duration is shorter in storage. Collecting during above freezing temps will both be more comfortable an undertaking, and be kinder to the health of the tree. Collecting too late in the season may allow for scion growth before graft healing has occurred. Scions with buds opening are likely to result in failure. For more information on actual grafting, please watch our video in the video section or on youtube (english speed graft).
Scionwood must remain turgid (full of moisture), but without being drenched in water. The easiest method is to place them in a zip-lock or twist tied plastic bag with a few damp paper towels around them or beside them. Damp means rinsed then wrung out, not dripping. Put the bag in the bottom level of the refrigerator, checking periodically to make sure the towel is damp, and the scions are plump and not molding. They will keep for up to 6 months if payed attention to.
This is also the method for mailing wood to us for grafting, remembering to add padding around the bag (ie- crumpled newspaper is fine) and send in a box.