Cordon Pruning

Frederic T. Bioletti

• Publisher: Home Farm Books
• Year: 2021
• ISBN:
  9781528769136
• Topic: Biological Sciences
• Subtopic: Horticulture
• Index: Biological Sciences

Frederic Theodore Bioletti (1865 – 1939) was an English-born American vintner. He studied at the University of California, Berkeley from 1889 to 1900, where he worked with prominent soil scientist Professor E.W. Hilgard. His work with Hilgard on the fermentation of wines under different conditions were significant in helping California vintners to refine their wine production practices and improving the resulting wines. Bioletti was the first chair of the Department of Viticulture and Enology and founded the grape breeding program at the University of California Agricultural Experiment Station. In this volume, Bioletti outlines different methods of cordon pruning, which refers to a method of vine pruning whereby the arms are scattered along the trunk of the tree so that the row of vines resembles a stretched rope or "cordon". Contents include: "Uses", "Disadvantages", "Establishment", "Direction of the Cordons", "The First Year", "The Second Year", "Winter Pruning", "Trellising", "Disbudding and Tying", etc. This volume will appeal to those with an interest in winemaking, especially the subject of pruning and other methods of vine training. Many vintage books such as this are becoming increasingly scarce and expensive. We are republishing this volume now in an affordable, modern, high-quality edition complete with a specially-commissioned new biography of the author and introduction on winemaking.

UNIVERSITY OF CALIFORNIA
COLLEGE OF AGRICULTURE
AGRICULTURAL EXPERIMENT STATION

CORDON PRUNING

BY FREDERIC T. BIOLETTI

INTRODUCTION

Nearly all systems of vine pruning can be placed in one of two groups: the head systems and the cordon systems. In the former all arms or short ramifications of the vine arise from the top of a comparatively short vertical trunk, giving the vine the form of a small shrub. In the latter the arms are scattered uniformly along the greater part of a comparatively long trunk which in some forms gives the vine or the row of vines some resemblance to a stretched rope or “cordon.” Various forms of cordons are used, differing in the shape and direction of the elongated trunk.

In the vertical cordon, the trunk is upright. This is an unsatisfactory form because it is impracticable to make the trunk more than about five feet long and it is difficult or impossible to maintain the arms along the trunk. The lower arms tend to weaken and finally die owing to the shade cast by the growth from the upper arms and to the tendency of the growth of the vine to go principally to the highest point. This is the only form of cordon that has been much used in California and is the commonest form of pruning adopted for the Emperor. All the old Emperor vines pruned in this way have lost the “cordon” character with all its advantages and have become simply high “headed” vines.

In the bilateral horizontal cordon, the trunk rises vertically for 2 to 3 feet and then divides into two branches which spread horizontally in opposite directions for 3, 4, or more feet. The vertical part of the trunk is kept bare and the arms are distributed every 8 or 10 inches along the upper side of the branches. This system is preferable to the last but is somewhat difficult to establish and to maintain in good condition and is inferior to the next in most cases. It is used in modified and incomplete forms in a few California vineyards.

In the unilateral horizontal cordon, the trunk rises in a quarter circle from the ground to a height of from 2 to 3 feet and then extends horizontally 6, 7, or 8 feet until it reaches the upper part of the bend of the next vine. The curved part of the trunk is kept bare and the arms are distributed every 8 or 10 inches along the upper side of the horizontal portion. This is the system most commonly used in Europe and it has been adopted lately by several growers in California. It has given good results with Emperor and, in experiment vineyards, with several other varieties, including the Cornichon, Ohanez, Zabalkanski, and Malaga, and it is recommended in preference to either of the other two systems mentioned.

This is the only system to be described here. It is used extensively in Algeria. It has been in use to a limited extent in California for over 30 years. Here, however, it has not been very satisfactory; both because it has not usually been carried out very skillfully and because it has been used for varieties and in districts to which it is not suited.

Uses. The cordon system is most suitable for vigorous varieties of table grapes growing in rich soil in the warmer districts.

Some vigorous varieties will not bear well when reduced to the size and shape of a small shrub. They require extension in the direction of the natural form of the vine, which is a far extending, climbing plant. Most of our table grapes have large bunches and large berries which do not ripen or color well, nor evenly, when massed together as they are in most forms of “head” pruning. They are also difficult to harvest when in this condition without much rough handling, which spoils their bloom, breaks many berries and injures their appearance and keeping qualities. The difficulty is much decreased by the horizontal cordon system.

Disadvantages.—The proper training of cordon vines requires more careful and skilled hand work during the second, third, and fourth year than most forms of head pruning. However, when the cordons are established, by the fifth year, the pruning is perhaps as simple as that of any system.

If the system is not carried out skillfully and carefully with a full knowledge of the proper methods, the vines may get into a condition which is worse than is likely with other systems. However, there is nothing very difficult to understand or to do in properly establishing a cordon, but the grower must be sure he understands the method and be prepared to do all that it requires if he is to make it a success.

ESTABLISHMENT

Plan of the vineyard.—As cordons should be used only with very vigorous varieties growing in rich soil, the vines should be given abundant room. A suitable spacing is 7 feet by 14 feet. The 14 feet between the rows facilitates cultivation, irrigation and the hauling out of the crop. The 7 feet between the vines gives trunks about 10 or 11 feet long of which 7 feet is horizontal and supplied with bearing arms. Each vine will have 98 square feet of soil which is about right for a large vigorous plant.

Direction of the cordons.—In determining the direction of the cordons, the slope of the land, the prevailing winds and the effect of the sun should be considered. The most perfect conditions are where the cordons can be run towards the south and in the direction of the irrigation and of the prevailing winds. As all these conditions cannot often be made to coincide, the best compromise possible should be made. None of these conditions is absolutely necessary but all are desirable. In most cases in the great valleys a north-to-south direction is the best compromise, but it may be necessary to run the rows from west to east if the irrigation water cannot be made to flow in the other direction.

THE FIRST YEAR

The first year, as with any system, the best and most rapid results are to be obtained only by thorough preparation of the soil and by the use of first-class planting stock, properly handled. No stakes are necessary and no summer pruning or disbudding of any kind should be practiced. Every effort should be used to stimulate a large growth by thorough cultivation and timely irrigation. The growth should be principally early in the season and should slacken in August and September. By October the canes should be brown and well ripened, all the leaves mature and dark green and there should be no light yellowish-green growing tips. If the vines are making new growth late in October or in November the wood will not mature when the cold weather comes and may be killed by an autumn frost. The vines should make a growth of several canes of from 2 to 6 feet, the first year and a correspondingly large root system. (See Fig. 1B.)

Fig. 1.—A. Top of young rooting directly after planting. B. Young vine after the fall of leaves. An average growth during the first season. c c c. Places where cuts are made in the first winter pruning. C. Top of young vine after the first winter pruning.

THE SECOND YEAR

Winter pruning.—In December or January, after the fall of the leaves, the vines should be pruned. Pruning consists in removing every cane but one with a pair of sharp pruning shears, taking care to cut as close as is possible without cutting into, the main part of the vine. The cane left should be shortened to two buds (see Fig. 1C) unless it is very large, in which case it is better left as long as it is thick (1/2 an inch) and mature. (See Fig. 8b.)

Trellising.—As soon as the vines are pruned, the trellis should be put up. An economical and efficient form of trellis is shown in figure 2.

A post is first put in at each end of each row. If the row is more than 200 to 250 feet long an extra post will be needed in the middle. An ordinary split redwood fence post, 5″ × 7″ or 4″ × 5″ and 7 feet long, is best. It should be placed with exactly 44 inches above the ground. This is most easily and accurately done by means of a post-hole digger. The posts should be well lined up and firmly tamped. At the end of the row from which the cordons run, the post should be 3 inches away from the vine. At the other end the post should stand 10 feet beyond the last vine. To allow a proper turning space, therefore, the vine at one end of the row should be 10 feet farther from the fence or limit of the vineyard than at the other.

A No. 11 smooth galvanized iron fencing wire should then be stretched between the two posts at 30 inches from the ground, leaving a loop or double wire of about 4 or 5 feet at each end.

Grape stakes are then driven close to every second vine on the side away from which the cordons are to run. Five-foot grape stakes are exactly the right length and should be driven 18 inches into the ground, leaving exactly 42 inches above. Six-foot stakes can be used and driven a little deeper. The wire is then stapled on these stakes at exactly 30 inches from the soil. The staples should not be driven in tight but left just loose enough to allow the wires to slip through when it is tightened. If the wire has been stretched properly, it will not require tightening until the next year.

Fig. 2.—Form of trellis suitable for a cordon vineyard. FP. Straining end posts. GS. Five-foot grape stakes at every second vine. P. Forty-inch redwood picket at the intermediate vines. Height of lower wire 30 inches, height of upper wire 42 inches.

A redwood picket, 1″ × 1″ × 40″, is then placed by each vine unprovided with a stake. This picket should be driven 6 or 7 inches into the ground, leaving 3 or 4 inches above the wire to which it is tied or stapled.

Another wire of the same kind but of No. 13 gauge is then stretched at 12 inches above the first. This wire will be just 2 inches below the top of the end posts and, if 5-foot stakes have been used, on top of the stakes. If 6-foot stakes have been used the wire must be stapled to the side like the first wire. The putting up of this second wire can be deferred until the next year, but is best put up at this time, especially where the vines are making a very strong growth.

It is very important for the regularity and appearance of the vineyard that this trellis should be put up straight and even. A simple guide (Fig. 3) can be made that much simplifies the placing of the wires and the driving of the stakes to exactly the same height. This guide consists of a piece of 1″ × 3″ batten, 42 inches long, with a cross piece 15 inches long nailed across the bottom and a nail driven into one edge at 12 inches from the top. (The figure is incorrect. The nail should be 30 inches from the bottom of the cross piece.)

Fig. 3.—Guide for insuring correct height of wires.

Disbudding and tying.—This important operation is often done improperly and too late. As soon as the young vines start to grow, they should be watched carefully and before any have shoots more than 4 inches long all shoots and swollen buds should be rubbed off except the longest and strongest one on each vine.

No shoot longer than 4 inches will be removed and most of them will be less than 1 inch. It will be necessary to go over the vineyard about twice for this first disbudding.

Tying to the picket.—The effect of this reduction of the shoots to one on each vine will be that the one left will grow rapidly.

(N.B.—This result is obtained only if the buds and shoots removed are ve...

Table of contents

• Cover
• Title
• Copyright
• Frederic Theodore Bioletti
• Contents
• Introduction Uses—Disadvantages