Monday, January 7, 2013

A Conversation About Pruning A Young Muscadine Grape Arbor

Young muscadine arbor
John, Thanks for posting the muscadine pruning videos. They are very informational. I was hoping you could answer a question about our muscadine growing/pruning situation. We have four Southland variety muscadines growing up four separate 8 ft arbor posts. Each post has wire running up all four sides. The vines get to the top and then we train them across the arbors in all directions. We let them grab onto each other to form a kind of natural canopy overhead. (Arbors are about six feet away from each other.)

We planted them last February and they did really well this year in terms of vines, and okay in terms of fruit. Most of our fruit actually came in the late Fall. Which surprised us. Anyway, it is getting time to prune, and I'm not sure how to go about it, since we can't really grow them in the T-shape due to our space limitations. If you could give me a recommendation on how to prune, it would be much appreciated. I can send you a picture or two if it would help. Right now, each plant has two to three "main" trunks from which most of the vines are coming.

In your case, I think you could do with only one main trunk per plant. At the top of each trunk you should choose a vine to train as a horizontal arm to cross the top of the arbor. Prune the ends off the arms when they begin to meet. Don't let them overlap.

Once these horizontal arms are formed, choose well-spaced side shoots along the length of each arm to train as fruiting spurs. Cut each shoot to 4 inches in length. Those short spurs will produce their own fruit-producing side shoots during the coming growing season. Next winter, prune those to 3 or 4 inches in length. And so it goes year after year.

As the vines grow older, you'll need to go back and do some renovation pruning, but that's another issue.

So I should have like an 8 ft tall trunk?

It appears that the segments (vertical and horizontal posts across the path) are not connected in any way. Am I correct?

Nevertheless, if the top of the arbor is 8' tall, each trunk should be 8' tall. It seems from the photo that you want the arms to extend across the path. If so, I recommend you have one main trunk growing up each post. Then have one arm from each trunk growing horizontally across the top and meeting in the middle. On those arms,  you'd establish fruiting spurs as described before.

Actually, I think you don't even need a trunk growing up every post. One trunk per segment and one arm growing horizontally across the path would be sufficient. Each trunk would easily produce an arm to extend across the path. As young as your vines are, you could remove the extra vines, especially those growing closest to the building and transplant them elsewhere.

Yes, the two arbors are not connected. So you are saying I should grow two of them to the top, then send one arm across each path? So it would be a 90 degree angle going up the post, then across the arbor top?

So then off the arm, the fruiting spurs would come. Won't these fruiting spurs be really long each year? Should I just let them hang down from the top of the arbor? If so, maybe I would nee to send the arms the other direction (in between the arbors) otherwise I would have a wall of vines blocking the pathway. Maybe then I should just do two plants, catty-corner from each other, and send them in between the arbors?

I guess for the year, I will need to keep a main trunk supported higher up on the plant. Maybe for a few more years until the trunk gets big enough. Right now it is pretty flimsy towards the top.

Yes. You could grow one trunk per vertical post to the top of the post. (Or you could have one trunk growing up one post and no trunk on the opposite post.) Then grow one arm from each trunk at a 90 degree angle (horizontally) to the center of the arbor. When they arms meet at the center of the arbor (above the path), cut the growth tips out of the arms so they don't overlap. They should butt-up to each other.

Then from those arms the fruiting spurs grow.  You see, when you cut the growth tip off of each arm, the arms will be stimulated to produce lateral growth along their lengths. Let all those lateral vines grow during the first growing season. The following winter (pruning season), select lateral vines that are about 8 inches or more apart. They will be the permanent foundation of future fruiting spurs. Prune them short to about 3 buds. Remove entirely any lateral vines between the selected spurs. This will give you enough room between the selected spurs (the permanent foundation) to reach your hand in and pick in the future.

The next growing season, those 3 or so remaining buds on the selected spurs will produce new growth. The following pruning season, prune the new growth to 2 or 3 buds. So it goes year after year.

Yes, the buds on those fruiting spurs will produce long vines during the growing season, but they can be shortened. Most of the fruit will be produced near the base of the spurs way up high, so you can trim the long vines that grow down and get in your way without harming the maturing grapes. When you trim them back, just make sure you leave enough foliage to feed the maturing grapes.

Got it. Thanks so much, John. This really helps

So regarding the pruning I will do very soon, should I select a main trunk and prune it at the top of the arbor? Then train the main arms this season (cutting them off when they reach each other)? I guess I would select which branches would become the main arms by picking the strongest looking ones?

Yes to all.

And here's a final question regarding which plants I should keep. In the picture, the two plants close to the house are in a bed with blueberries. The other two plants are in a bed that has rotating vegetables (anything from carrots to tomatoes to potatoes to peas, lots of stuff, changing year-to-year). I know the grapes and blueberries are both shallow-root plants, but since they are both perennial, do you think it would be better to leave those plants in place and move the plants that are in ever-changing vegetable beds? I guess it's a question of competition with blueberries vs. being in an oft-disturbed vegetable bed.

Companion planting can be a good idea, but some plants don't make good companions. Check around on the internet or in books on the subject to see what might work for you.

Another thought: Most vegetables prefer full sun. Blueberry shrubs nearby might not allow sufficient exposure.

Still another thought: Blueberries like low pH. Some vegetables might prefer higher pH than what blueberries need.

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