Monday, April 4, 2011

Pruning Grapes and Leonardo di Vinci's Vitruvian Man

Well, it was an incredibly beautiful, SEASONAL spring day, today. I called the village library to check with our very own village weather prognosticator; yes, the village SNOW WITCH! So what's up? Is spring here?

I call. "Is the Snow Witch in?" "No," comes the casual reply. "So, is her forecast still posted for the year?" The librarian on duty doesn't hesitate, just gives me the bad news.

"The Snow Witch says three more measurable snowfalls."

Damn! I asked, "When was she last in to update her findings?"

"She came by this morning," was the droll reply. Damn! Damn! Damn!

You see, our village Snow Witch is not wrong about these things. Further consultation with the weather prognosticators in the village gives additional information; one of the snow falls will be a heavy one.

"Ugh!" My mother had crocus blooming this morning. My hepatica are green! Come on!

No wonder the Snow Witch is not in!

Regardless, today I begin working on my yard. I still have a couple feet of snow in places. I rake where I can. This is the latest in six years I have pruned my grapes. They are on my list for today.

If you have never pruned your grapes, the chore may seem incomprehensible. If that is the case, I recommend cutting off all but 6'to 7' of the vines so you can see what you you are doing.

This picture shows two grape vines clipped back to 6' or 7'. I did that in the fall.

Next keep in mind, that if you mess it up, there will be a next year. When keeping grapes, your goal to to prune them to increase your yield. I like to trim back the vines to 6' to 7' in the fall to remove material that may have been exposed to fungal diseases. I leave the rest to provide additional protection in the winter to the crown.

During the growing season I tie my grapes to wires running north and south strung between two 4' posts. This allows the prevailing NW to SE winds to provide good air circulation. This is supposed to prevent diseases. Grapes are susceptible to many of the same diseases and pests which affect roses. To date, I have not been affected by any pests, nor diseases.

I have tried to illustrate a couple things. The red parts are the oldest parts of my grape vines. Those sections boxed in pink our this last year's growth. The wires I have high-lighted in blue. Three years ago's growth is orange. The year before last is in yellow.

These parts I have circled in yellow are last year's growth. Cut them back so you can see what you are doing. The bark on the vine that appears to be peeling is typical of a grape vine and nothing to be concerned about (green rectangle).

The first year, I let them grow. The next year, I started to try and see the form of Leonardo di Vinci's "Vitruvian Man". The farther you get from the trunk of the grape the less vitality the budding spurs have. Also, you want to prune before too much energy is expended with leaf development. In central Wisconsin, you want to prune before April 10, preferably between the last weekend in March and first weekend in April.

Circled in yellow are the coming fruiting buds for this year.

These vines actually were tip die-back and are dead. This is why I do not do my pruning all the way back in the fall.

These vines are some left from last year's growth. Cutting these into foot-long lengths and burying about 2/3 of each in a potting medium, keeping them moist, and placing them in a protected spot will encourage them to root. I usually use Rootone to root them and get 100% to root. They root so easily, if you wanted to forgo the Rootone, they would most like root anyway. In that case, I would attempt to root a few extra to be sure I got the number I intended to plant.

All finished!

I have two grape varieties, Frontenac and Othello. My vines are approximately 6 years old now. The second year in the ground, one of the vines were inadvertently clipped off at the ground. I thought at the time that was to be the end of the one, but the next year it grew back, only lagging for a year or so (the one circled in green).

You want to leave 6" to 18" of branching running off from the trunk both left and right at two levels (equivalent to the legs and arms). The length of the branches should include two to three bud spurs. When you have mature vines you will eight to twelve fruiting buds per plant. Think of "Vitruvian Man" when pruning.

Grapes do not like competition with grass and weeds. I do have mine underplanted with strawberries, which seems to work well, however. I use a 10-10-10 fertilizer and water them on a weekly basis. To have grapes grow well, the most important ingredient is that they be well-watered, especially when the grapes are growing quickly after the summer solstice.

No comments:

Post a Comment