Bulletin No. 856 (1920)
Currant-Grape Growing: A Promising New Industry
George Charles Husmann
RINGING THE VINES
It has been found that in order to make the blooms set and secure full yearly crops of grapes the vines must be ringed every year. This ringing consists of making two parallel incisions through the bark and cambium layer around either the trunk, the arms, or the canes of the vines and completely taking out the bark and cambium layer between the two parallel incisions. (Pl. V, fig. 1.) This does not interfere with the upward flow of the sap through the outer ring of undisturbed wood, but where the ringing occurs checks the returning flow while the ringed place is healing. (Pl. V, fig. 2.) The effects of ringing are a full setting of fruit and much larger berries and clusters. (Pl. IV, figs. 1 and 2.) The ringing is done either with a large-bladed pocketknife or with special tools made for the purpose (fig. 3).
In ringing several factors need special consideration. The time the ringing is done is a most important matter and is related to the blooming period. If done either too early or too late, the desired results will not be obtained. It is best to do the ringing when the clusters are partially in bloom or in the middle of the blooming period. The blooming period being of relatively short duration (usually not more than 10 days), when ringing on an extensive scale it is advisable to start just as the first flowers open and continue ringing throughout the blooming period. The effects on fruit setting are noticeable with vines ringed after they stop blooming.
The depth of the incisions is also very important. They should be made entirely through the cambium layer, and the matter between the two incisions should be immediately and completely removed. The results obtained will depend on the thoroughness of this part of the operation.
The width between the two parallel incisions is also an important matter. The distance between the incisions should be no wider than is absolutely necessary to allow a narrow circlet of the bark and cambium to be removed. On the arms and canes of vines a circlet one-eighth of an inch wide is sufficient; for large arms and trunks of vines a circlet one-fourth of an inch wide is necessary. If good judgment is used in doing this work the circlet removed on the vines ringed while in bloom should be completely healed over in six to eight weeks, or by the time the grapes are ripe.
Fig. 3.—Some tools used in ringing vines.
Another important factor is the part of the vine to ring. The effects on the vine are manifest, of course, only beyond the place of ringing. Hence, the entire vine is affected by one ringing of the trunk, but when either arms or canes are chosen all of them must be ringed, in order that the entire vine may be affected.
|1 For further information on the adaptability of resistant stocks to soils and other conditions see Bureau of Plant Industry Bulletin 172, entitled "Grape Investigations in the Vinifera Regions of the United States with Reference to Resistant Stocks, Direct Producers, and Viniferas," and Department of Agriculture Bulletin 209, entitled "Testing Grape Varieties in the Vinifera Regions of the United States."|
In the experiments conducted at the Fresno Experiment Vineyard, 12-year-old ringed Panariti grafts on 10 different resistant stocks trained to stakes (vines 8 by 8 feet apart, or 680 to the acre) during 1917 and 1918 gave average annual yields per acre ranging from about 5.8 tons (Pl. IV, fig. 1) on the poorest stock to 10.35 tons on the best stock, the average on all the stocks being nearly 7 1/2 tons. The check vines with like treatment and care averaged only 2 1/3 tons to the acre (Pl. IV, fig. 2). Ringed 5-year-old Panariti grafts on 18 different resistant stocks, with trellis training (vines 8 by 8 feet apart, or 680 to the acre) during 1917 and 1918 averaged annually over 5 tons to the acre, while the check vines averaged only 1.9 tons to the acre.1
|PLATE IV. Comparison of Two Vines of the Panariti Variety|
|These two vines, grafted on the same stock (Rupestris St. George), growing side by side, of the same age, and comparable in every way, received the same attention and care except that a ring of bark one-fourth of an inch wide was removed at blossoming time from the trunk (see arrow) of the vine shown in figure 1. Both vines were photographed at fruit-ripening time.|
|Fig. 1—Panariti (Ringed Vine) Yielded 33 Pounds of Grapes||Fig. 2—Panariti (Not Ringed) Yielded 6 1/2 Pounds of Grapes|
|PLATE V. Two Views of a Panariti Grape Vine Grafted on Aramon x Rupestris Ganzin No. 1.|
|Fig. 1—Trunk of Vine, Showing the Ringing Done on May 23, 1917, When the Vine was in Bloom.||Fig. 2—The Same Vine, Showing the Ringing on its Trunk Healed Over, July 15, 1917, When the Fruit was Ripe.|