As part of a series on pruning and caring for different plants, here’s a timely guide to trimming your grape vines
Houzz UK contributor and award-winning landscape and garden designer. Claudia de… More
December, when the plants are dormant, is the best time to prune vines to ensure you have a bountiful crop of delicious grapes next year.
Why should I prune in winter?
Grapes or fruit are produced on one-year-old wood. If you leave a vine to its own devices, it will grow a dense mass of old wood with little fruiting wood. So to get your grape vine to grow healthily and produce the best-tasting fruits, December, when the plant is dormant, is the best time to prune each year.
Prune grape vines before Christmas, before any sap rises in the new year. Vines tend to bleed from any pruning wounds that are made too late and this can weaken the plant. Remove any dead or diseased wood and always clean your shears in-between cuts in case you spread disease.
We prune to remove long, vigorous, whippy growth and shorten the side branches to a few buds, which helps to create gnarly fruiting spurs. This is called spur pruning.
Choose a sturdy cane and prune back shoots that have produced grapes in the summer just gone, cutting back to around two or three strong buds. These will go on to produce shoots for the grapes the following year on new young stems.
Read a beginner’s guide to pruning
How should I support my vine?
Support for a vine is very important to encourage the plant to grow a structure that’s best for harvesting. By using a trellis or wire, you’ll be able to tie in shoots throughout the year, creating an orderly system of evenly spaced vines. Be careful not to tie the stem too tightly, as this will constrict growth; use a loose twine or tape, which will decompose over time and allow the branch to support itself once it’s strong enough.
Make sure the support wires are around 38 to 46cm (15 to 18in) apart in order to cut each new stem back to whichever wire it has grown to that year. When the vine has reached the required height, you can cut it back to the highest wire.
Horizontal branches should also be cut back to two or three strong buds. Tie these into the wire or trellis support.
In the new year, when the growth really starts, you can prune any of the side shoots, as well as any shoots you think are too tall, by reducing them to just one leaf.
To make sure you get the best grapes for eating, reduce the number of bunches to one per shoot, so they have the chance to plump up and sweeten.
Need advice on looking after hedges, too? Here are 8 invaluable pruning and maintenance tips
How do I prune to create a ‘standard’?
If space is an issue, you can grow grape vines in containers quite successfully. Even though you may not get a huge amount of fruit, and vines are slow to develop as a ‘standard’ – a single stem with a head at the top – they do look good. Being in a container also means you can always move them to get as much sun as possible.
If you’re planting a vine in a container, you want to achieve a single stem. When new shoots develop in spring, snip or rub them off the main stem. This will encourage strong stems to shoot up from the top. When these new shoots have grown to 7 or 8cm (3in) in length (around five stems is a good number), take out the tips of each one, which further encourages side shoots to spring. This will form a nice strong head to your plant.
In the first year, your vine will bear no fruit; in the second year, prune the top again, snipping back the stems at the head to 7 or 8cm (3in). It’s best to remove any flowers in the first two years to allow the plant to put its energy into the third year, when it should produce at least three good bunches of grapes.
This three-year method of pruning your standard vine also applies to any new young vines, whether grown outside or inside – but your indoor vine may need a bit more help with pollination.
By year three, you should have a good head on top to support the bunches of grapes.
How will I know when my grapes are ready?
It’s very easy to get overexcited when you see a bunch of grapes and think they’re ready, but often you’ll end up with a sour, bitter taste if you pick too early. Grapes need to be soft to touch, be plump, and feel as if they’re full of juice. If the grape is a white variety, for example, you’ll notice the skin turning from a very deep green to a thinning yellow (although colour doesn’t always indicate whether they’re ready).
Powdery mildew may affect grapes and can be due to poor air circulation. Vines can also suffer from Grey mould and Downy mildew. To prevent disease, clear away any fallen leaves that may be carrying spores and mulch plants to avoid stress caused by drought.
Under glass, make sure your vines are kept well ventilated and water at the base, as overhead watering may increase humidity around the plant, which in turn will make the plant more prone to any fungal disease.
As vines are heavy feeders, from February onwards give them a good, balanced feed.
How much room do the roots need?
Vines like to be grown in deep, free-draining soil in a sunny position; that’s why many people choose to grow them in a conservatory or greenhouse.
The root system is very big on a vine, so it’s important you give them the depth they require and a lot of room. Sometimes it’s better that the roots are planted outside the conservatory and the vine trained inside through gaps at ground level. Plant them opposite the greenhouse or conservatory door and train the stems along the sides towards the door.
Good grape varieties to try
- A good outdoor variety of grape that also does well in pots is ‘Black Corinth’. This small red grape is seedless and can be dried to make currants.
- ‘Boskoop Glory’ has lovely colourful foliage in the autumn and small black grapes, though they are a little pippy.
- ‘Strawberry’ is a very vigorous variety that has aptly named pink-coloured and strawberry-tasting grapes.
- For a good sweet white grape, opt for seedless ‘Interlaken’.
- For inside a conservatory or greenhouse, try ‘Regent’, which produces a lovely sweet black grape.
- ‘New York Muscat’ is a good black grape and also disease-resistant.
- ‘Chasselas’ is a lovely early-season white grape.
What tips do you have on growing grape vines? Share them in the Comments section.