Grape Grower's Notebook April 7, 1999

Vine Trunks

Why do some vineyard owners anguish over vineyard layout and design, site posts with a surveyor's instrument, plant vines with a plumb line and then cede control of the vineyard to vines that are permitted to grow into the aisles and generally create chaos? We don't know the answer to that one, but we have visited a few vineyards that seem to have followed that approach to viticulture.

First, ceding control to the vines does not take place during the first three seasons. During this time, the grower has ample opportunity to exercise his/her will over young trunks, keeping the vines perpendicular to mother earth and in the general spot they were meant to occupy. If the owner is doing his/her job to maintain control during this period future problems are avoided. "West Point in the vineyard!" Lucie Morton calls it, and the analogy is an excellent one.

Second, ceding control is never a conscious decision on the grower's part. It's just something that happens. Like waking up one morning and discovering that you are the parent of a teenager. Abandonment of a vineyard, on the other hand, is a conscious decision. If you are looking for support for the abandonment option, ceding control to the vines is a good place to start!

Here are a couple of suggestions for assuring that your vineyard enters its fourth, fifth and subsequent seasons with West Point as a model. As usual, in the spirit of sharing, we would like to benefit from your ideas on this subject, so let us have them.
 

The Sky Hook

When you want to "straighten" your back (and vineyard owners do a lot of this), you stand up and stretch, throw your shoulders back, and flex your muscles. Help your young vines do the same thing. In their second season (and keep in mind that this applies to replacement vines as well), using degradable twine (not nylon, or monofilament), tie a bowline knot around the trunk just below the remnants of a lateral shoot or the stump of strong tendril from the previous season. Pull up on the twine while using your other hand to pull down on a taught, higher wire. Wrap the twine around the wire two or three turns, tie off with two half hitches and let go of the wire. [Special note on second year GRAFTED VINES: not too much tension here! Give that graft union another year to become at one with the root stock. In the third season, you can give it all the tension you wish.] At this point, you will see the young trunk mimic your back straightening technique (you can almost hear it groan with satisfaction). It thinks you have invented a sky hook, so it heads for the sky.

The bowline should be tied with an eye large enough to permit annual growth. If there is no lateral joint ("Y") or tendril stump to put the eye around, put a clove hitch on the top most wood of the trunk where girdling will not be a problem.

Bowline eyes should be cut off at the beginning of the third season. Even with degradable twine, eye, knot and twine may become covered by annual wood growth and begin to girdle the trunk. If necessary from the appearance of the trunk at the beginning of the third season, the procedure may be repeated using new twine, but this is seldom necessary.

If for some reason you do not have a high trellis wire with sufficient tension to use this procedure, supplement a stake tied to the trellis wire with a nail at the top to permit tying off the twine as above. Don't bother to tie the vine trunk to the stake.

If the knots mentioned above are not in your repertoire, master them! They will make all sorts of vineyard work much easier. If you have other favorites, let us hear about them.
 

The Splint

No matter how good you are at training vines, there will inevitably come a day when you notice a curved trunk or one with a crook in it that slipped through the enforcement system. If it bothers you the way it bothers us, you will want to fix it. If it doesn't bother you, maybe it should.

Minor deformities in young trunks may (probably will) become major ones causing extra work for you and sometimes significant inconvenience. A vine permitted to curve toward one of its neighbors, or into an aisle, is technically growing laterally as well as vertically. As it matures, lateral growth seems to dominate over vertical. When you ultimately try to regain control, you will discover that this tendency toward lateral growth has produced a trunk that is longer than the rest of your vines and consequently has a higher head and fruiting zone. Sufficient trellis to support annual growth and fruit has literally been passed by.

So, if curves and bends and crooks, etc. bother you now or later, how will a few minutes work correct the problem? The answer is a splint on the trunk. Center a Quick-Grip clamp (which may be operated with one hand and has padded jaws to protect young wood) on the objectionable area of the trunk with the latter sandwiched between two 18" pieces of firring strip. Draw the clamp as tight at you can get it. Tie the splint (old clothes line works well) at top and bottom and go have a glass of wine. One or two days later, take the clamp back to the vine and you should find that you are able to close the splint even tighter. Retie. At this point, you let nature take over. The splint stays on all season and winter is okay, too. The trunk will grow the way you want it to and you will have eliminated the offensive deformity.

Obviously, performing this procedure in the first few seasons of growth will make the work easier. And, the work should be performed early in the season to permit maximum corrective growth. However, don't be afraid to try this procedure on a vine of any age at any time of year to attack whatever trunk deformity is bothering you. Nature will still go to work for you. Of course, for an older trunk, you may need a stronger clamp and something stronger than firring strips (see note below on wood).

Finally, be sure to clear off all material at the beginning of a new season and reinstall if desirable.
 

Note on Wood

The varying abilities of vitis varieties and their root stocks to add diameter to trunks during the growing season is something that must be kept in mind when working with these and other corrective measures. For example, in the case of a vinifera variety grafted on stocks which result in vigorous growth (5bb, SO4, C5, 420A) the third growing season may be too late for effective use of the sky hook. The same variety on C 3309 will give you an extra season.

Own rooted varieties are all over the map as far as propensity to add wood. In its third year, a Baco Noir vineyard will look like it has been there since before prohibition. In other words, if you don't use the sky hook in the second growing season, you may or may not have difficulty applying it in the third.

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