Pollinator May Be Provided By Grafting

Press, Volume CIII, Issue 30543, 11 September 1964, Page 6

Pollinator May Be Provided By Grafting

Some gardens have a fruit tree which does not crop well because it lacks a suitable pollinator. There may not be room in the garden for another tree to rectify this. Even when there is, it takes some time for a new tree to come into cropping.

This deficiency can, however, be overcome by grafting. This is the joining together of different but closely related plants so that they grow as one. All grafts consist of two parts. One is known as the rootstock, usually abbreviated to just stock, which is the basal part of the plant that forms the root system. The other part is known as the scion, which forms the uppermost portion of the plant, the trunk and branches. There is only one stock in a graft but each stock can have a number of scions grafted on to it. Apart from close relationship between stock and scion, successful grafting depends on several other factors. Most important is cambial contact between stock and scion. The cambium is ■ found immediately below the bark or rind. Both stock and scion must be healthy—free of disease and pests. The scion material must be selected'from vigorous, one-year-old growth and should be in a dormant state at the time of grafting. It is usual to collect it during pruning, after which it is bundled, labelled and heeled in in a cool shady place, such as at the foot of a south facing wall. The sap should just be rising in the stock for grafting to be carried out; this usually occurs towards the middle of September. AH cut surfaces should be sealed, either with grafting wax or one of the proprietary sealants available. PROCEDURE One or more of the leaders of the tree should be cut back to a suitable height; removing all lateral growths except those close to the butt. Care should be taken to avoid any bark damage in this operation. At least one leader should be left completely uncut. This will act as a sap drawer, assist in feeding the tree and aid in quicker healing. All cut surfaces of the limbs should be lightly pared smooth with a sharp knife. There are a number of

different grafts than can be used and only two kinds are mentioned here, the rind graft and the notch graft. RIND GRAFT In grafting of any kind it is important to have a knife that is capable of taking and retaining a razor sharp edge. Take the scion wood and wash it free of all grit, cut into pieces each having five buds, make the cuts immediately above the buds. At the base of one of the pieces make a long sloping cut about 2in in length. This should be made in one movement so as to produce a straight, even surface. This is not easily achieved unless one is practised at it and experimenting with unwanted material is advocated. On the headed bark root stock, make a vertical cut of about 2in in length through the bark to the wood behind. Lift the bark with the tip of the knife, sufficiently to allow the tip of the scion to be inserted. Then carefully push the scion downwards behind the bark until none of its cut surface is visible. Branches up to 2in in diameter will require only two scions, those of 3in diameter will need three. Four can be inserted on still larger ones. This ensures against loss, and unwanted shoots can be cut away at a later time. On completion of all grafts, binding with tape or raffia is advocated to give added support and ensure scion stock contact. All cut surfaces and tied areas should be. covered with grafting wax or similar sealant to prevent drying out, or water and disease entry. NOTCH GRAFT The notch graft is more difficult, requiring more precision in its “dovetailing” and is comparable to joinery. A notch about 2in in length is cut into the stock using a sharp, heavy knife. A similar cut. is then made on the scion to correspond with that on the stock. It is preferable to cut the scion rather too large so that it does not quite fit and then gradually pare it down to size so that it fits tightly. To secure in position, a panel pin is driven through the scion into the stock. Particular care must be taken to line up the cambiums of both stock and scion

otherwise a union is not possible. Binding of the completed graft is again advocated before sealing the cut surfaces and surrounding areas. The grafts should “take” in about six weeks. This will be indicated by the buds on the scion growing away. When this stage is reached any ties should be severed to prevent strangulation. The strongest growth should be allowed to grow unchecked but other buds that develop should have their growing point removed at the second leaf. Sucker growth which develops should be allowed to remain except those immediately around the grafts.

Do not forget to include the tree in your spray schedule, for pests such as aphis and leaf rollers, can cripple the growth. Six feet of growth, or even more, can be produced from the grafts during the season. During the next winter all sucker growth should be removed as well as those branches that were left as sap drawers. Shorten the leading growths from the scion' by about half. Subsequent pruning would be as with any other young tree. As the framework develops it may be found necessary to remove some of the original grafts where more than one was used on the butts.