BUDDING OF CITRUS TREES

New Zealand Journal of Agriculture, Volume 74, Issue 2, 15 February 1947, Page 157

BUDDING OF CITRUS TREES

By

J. E. HUME,

Orchard Instructor, Tauranga,

BUDDING of citrus trees may be done over a fairly long period, usually from November to March, if the weather is reasonably good for steady growth. During this period the sap should be flowing freely in the stocks. For general purposes February is the most suitable month, as the buds will then remain dormant throughout the winter, while those inserted earlier will start to grow before winter and be more subject to frost injury. Another disadvantage of early budding is the difficulty of obtaining suitable buds, as many which would be otherwise suitable will be making growth.

OOD bud-sticks are well rounded and mature, about lead pencil thickness, not more than 1 year old, and taken from healthy x trees that have carried good crops of fruit, true to type, for several years. Avoid taking buds from suckers, water shoots, or any wood showing malformations or excessive thorns.

Selection of Buds

The most suitable bud-sticks are dark green, with pale-green angular tips. The tips should not be used, nor should the base buds on the sticks, . because they are invariably weaker. Plump buds taken from between these two portions should give the best results. On removal of the bud-sticks from the tree the leaves should be cut off, but a part of the stalk or petiole by. which to handle the bud should be left. It is preferable to do all trimming of the sticks in the shade and to keep the budwood wrapped in damp sacking, as drying out will affect it detrimentally.

If supplies of budwood are convenient to the nursery, gathering it at least daily jis preferable. Any which has to be transported a considerable distance should be carefully wrapped in damp cloth or sphagnum moss.

Preparation of Stock

Only good strong stocks should be budded and any thin or small ones discarded.

The buds of sweet orange and grapefruit should be inserted at least 9in. above the ground; for standard lemons at least 12in. is advisable. To avoid interference with the operation, clearing the stocks of all leaves and shoots up to a little above the point of budding is a good practice. Inserting the Bud Budding must be done neatly and quickly to prevent drying out of the bud shield, and always with the utmost care to avoid damaging the bud. Inserting the bud on the shaded side of the stock is best. With a sharp knife, an upright incision about lin. long and the depth of the bark is made in the stock; across the top of this and at right

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angles to it a second cut Jin. long is made, forming a letter T. With the point of the knife or the shaped end of a proper budding knife the edges of the upright cut are opened out for about Jin. from the top, baring the white under surface (cambium layer) and allowing for the entry of the bud shield.

RULES FOR BUDDING

Use budwood only from speciallyselected, proven trees. Carry out all operations with speed - and precision. Take particular care with tying to exclude air and moisture.

In taking a bud the bud-stick is held with the upper end toward the operator and the shield shaved off by a slicing motion of the knife, starting Jin. below the bud and finishing the same distance above. The bud can be prevented from falling by holding it on the blade with the thumb. The bud is handled by the small piece of leaf petiole which was left on, inserted right way up in the incision in

the stock, and slid gently down until it fits snugly into position. The operation is completed by tying with suitable material such as raffia, specially-prepared budding tape, or strips of rubber, starting the tie at the bottom. The tie should be firm to exclude air and moisture, but the bud must not be covered.

Treatment After Budding The buds should be examined 2 or 3 weeks after budding and the ties loosened or cut on the opposite side to the bud to avoid restriction of the flow of sap. If budding tape or rubber strips have been used, they may be left unattended longer. During this inspection it may be found that some buds have failed to “take”; the petiole will probably have shrivelled and turned brown but still be adhering to the shield. If the stock is still in a suitable condition, another bud may be inserted higher or lower. Buds that are healthy and growing can be recognised by their green appearance. If - the petiole is still attached, it will be pale and will drop off at the slightest touch.