Old grape vine

AshleyCanterbury

I moved in to a new house and inherited a grape vine with three woody trunks. Last summer the vine covered the whole side of my house and was great, but not very productive and I'd like to retrain it.

Is cutting back lower than those knobbled trunks risky? They kind of grow haphazardly, one trunk slightly slitting, and I had thought about taking it down to ground level and train one new single trunk - the vine clearly has very well established roots now. 

Katfish

It is surprisingly hard to kill a grape vine, particularly if it has found a sunny sheltered spot that it likes.  If you cut the knobbled trunks you will stop the growth of those trunks in that direction, but they will then start to develop their main trunk off another side shoot.  So you need to really think about the shape of the plant that you would want.

I think sometimes vines do stop producing fruit and it is at this point that it's best to start off another plant if you are wanting some grapes.  

Fortunately it is also surprisingly easily to propagate grapes.  I once pruned my vines in the spring and decided to use some of the cuttings as seed markers as I'd run out of canes.  I was quite surprised to find leaves appearing on them after a few weeks and decided to save a few of them to give to friends.  Basically you just need about 2 feet of one of the newest branches with 2-3 possible bud joints on them (sorry, I've forgotten the correct name, but the rings on the branch that will be a few inches apart).  Make sure you know which is the end that was nearest the trunk and put that about 6 inches into the ground.  Then leave it for several months without moving it.  In the following season you should be able to see lots of roots and you can plant it wherever you want it to mature.

To get a vine to produce fruit the trick is in the pruning, which includes pruning in the spring and the summer.  I'm afraid my technique is to stand and look at the plants and decide what looks like it will develop nicely and what will take too much energy from the other branches.  It's not very scientific but having had an abundant grape harvest for 15 years it does seem to work.  It does mean that I can't give a lot of written guidance on how to prune grapes, other than don't worry too much about it.

I think if I had a mature vine that covered the whole house and was lovely to look at I'd probably keep that vine in the same shape and not prune it right back.  Then take a few cuttings and develop those ones for fruit.

Also check the soil that it is in.  If it is next to the house is it in a small bed that might need some fresh soil?  Grapes are hungry and thirsty plants.

AshleyCanterbury

Thanks for your advice Katfish! 

I'm hoping there is still some potential to get fruit from it - the neighbour's had lots of bunches and was planted at the same time. I think it just needs a bit of care, so I'm going to cut down the two weaker  trunks to the ground and the last/third one I will cut it a little lower and choose one new side shoot from it this year to train up.

Fingers crossed!

Dovefromabove

I would leave the three main branches and cut every side branch back to two or three buds ... they will produce the growth which will bear the fruit this year.

That's how I prune mine and we get loads of fruit. 

I suspect lack of fruit last year may have been down to a very dry spring ... I gave mine a lot of water.