I have grown some cuttings from an old vine (that produced fruit) in the UK.

The plants are now about 3 years old and appear healthy with lots of foliage but have never flowered.

Any tips on how to get these vines to fruit?

Many thanks,
Martin

I doubt if it is the Roundup that causing the symptoms. Normally, after about 7 days, Roundup that was sprayed on the ground or soil, will have no effect on green parts of any plant.

OK, with that out of the way;

First Jim, where are you from? I’m asking this, because it can be that it is the end of summer and that the grape vine is steadily going dormant. The yellowing of leaves from the bottom, is normally a sign of upcoming dormancy.

The fact that your grape vine isn’t growing as vigorous as before, can also be a sign of dormancy.

Do you have pictures of the vine? It will most certainly help.

I planted my first grapevine this year in my backyard. It’s a Vanessa seedless table grape. About 2 weeks after planting, the vine started growing at the rate of about 1 1/4 inches per day.

2 weeks ago, it surpassed the height of the 4 foot stake that I was training it up. I extended the height of the stake by attaching a thin piece of bamboo to the top of the stake but while I was doing this, the vine fell over and the growing end touched the ground.

Since that day, the vine has only grown about 1/2 inch over 14 days and the growing end looks dead. The leaves closest to the ground are also starting to rot and curl. The leaves turn yellow at the edges first and the yellow eventually spreads to the center.

It’s possible that ’round up’ was carefully applied to the area that the growing tip fell on when it hit the ground but if so, it would have been applied more than 30 days (and 20 rainfalls) prior.

Is there anything I can do to save this vine or will I need to start over from scratch next year?

You have a point there, but the reason I do not remove grapes prior to flowering, is as you said; it will effect fruit set. If you grow grapes for making wine, this will not be a problem, but if you grow grapes for eating and export, like I do, you don’t want too compact grape bunches. Removing leaves can result in the vines not aborting enough berries and will stick to buches – these berries then have to be removed by hand (expensive and time consuming process).

It all depends on how old your vines are and what trellis system you use. Shoot diameter also determine if you will give the shoot a bunch or not.

On a gable trellis system with a planting distance of 3 meter (row) by 2 meter (between vines) I leave about 25 to 28 bunches per vine.

It could be because of a fungus disease (powdery milldew for example), or high humidity inside the green house.

Do you use mist irrigation in the green house?

The roots of the grape vine can penetrate the soil very deep, especially to look for water. I don’t think planting a grape vine on a drain field would be such a good idea, as the vines will for sure go after the “water” that runs in the drain field.