Can you over-prune Concord grapes?
I love my Concord grapes. I love the way they look as a live privacy screen on my fence. I love getting to eat them off the vine in the fall.
So when I had to severely prune them back last fall in order to make repairs to my fence, I worried that I might have killed them. Over-pruning can really impact grape production.
You can see the hatchet job I did on this poor vine. Because all the canes had twined through the fence, I had to lop them all off. Not looking good…
Here, you can see a few leaves have sprouted and a few more buds are underway. Phew. This vine gets to live to see another season.
That said, with the severe haircut I had to give this vine, I won’t be expecting a bumper crop of grapes.
On this vine, below, I was able to preserve a few canes with buds, so I knew this one would come back.
You can already see that there will be several new canes on which to bear fruit. There should be plenty of grapes from this vine come September.
So I’m happy to report that it’s practically impossible to over-prune and/or kill concord grape vines.
Nevertheless, I should say that even in the best of circumstances pruning is an art of keeping balance: prune too much and you’ll wind up with a small crop; prune too little and you’ll get too many bunches of grapes of lower quality fruit. The trick is to prune just right.
One of the reasons I grow Concords (aside from the fact that I love how they taste) is that they are a very forgiving variety. Great for anybody who doesn’t have time to become an expert vintner.
Along with the question of whether you can over-prune, is the question of when should you prune.
Pruning can be done at any time between leaf drop in the fall and bud break in the spring. But beware that pruning in the fall in colder regions may increase susceptibility to freeze injury compared to later pruning. Since I live in Zone 5 with real winters, I usually postpone pruning until after winter’s coldest temperatures. Postponing pruning also gives me a chance to assess cold injury and adjust pruning to compensate for injury losses
Here’s a great primer on grape vine pruning, for anyone who is unsure of what or how much you should prune.
[Updated Nov 23, 2022]
I got black spot I guess it a fungus. So my thoughts were to prune back survely and from what I’ve read need to clean up all the mumes. I only have 3 plants there is lots of grapes guessing about 60 gt of juice but there all bad. What do you think of my plan
Black spots on your Concord grapes can definitely be an indicator of a fungal disease. But it’s also possible that you could have pest infestation.
Common causes of black spot include diseases like black rot, anthracnose, or pests like grape flea beetles.
Pruning is definitely an option. At the very least you’d be improving air circulation and reducing humidity, which can facilitate the growth of fungal pathogens.
You could also try removing infected leaves, clusters, and any mummified grapes to reduce the source of inoculum.
Also make sure to control weeds around the vines, as they can harbor pests and diseases.
Avoid wetting the foliage while watering, as this can create a conducive environment for fungal growth.
If necessary, apply fungicides to manage the disease. Note that it is generally recommended to begin a preventative spray program early in the season before the symptoms appear. The kind of fungicide to use will depend on the identified pathogen. Common options include:
Black Rot: Products containing mancozeb, myclobutanil, or ziram can be effective.
Anthracnose: Fungicides with active ingredients like mancozeb, captan, or copper-based fungicides can help.
Your best bet is to consult with your local extension service or a plant pathology laboratory for accurate diagnosis and management recommendations.
Good luck!