Pruning the Greenhouse Vine

Pruning the greenhouse vine is part story and part gardening lesson on how to tackle an overgrown grape vine.

The pruning took some time, as tidying up detritus – leaves, incursions of ivy and honeysuckle – was necessary too. This was not just for tidiness, but also to reduce the likelihood of pests and disease. The vine is basically healthy and I’d like it to stay that way!

This type of gardening task does take a while, but if you only have an hour or two at a time, it is easy enough to complete in stages.

A brief explanation – the story behind pruning the greenhouse vine

The grapevine and greenhouse are in my late mother-in-law’s house or rather, garden. Originally planted and cared for by my late father-in-law, because of covid and other matters, I haven’t been able to get up at anywhere near the right time to prune for too long. Rather than risk losing the vine which produces sweet dessert grapes (and, let’s be honest, has sentimental value too) I’ve embarked on a plan of restorative pruning to bring the grapevine back to its productive glory. Oh and mend the greenhouse too.

Best time to Prune a Grapevine

Grapevines need to be pruned when they’re dormant as they ‘bleed’ or ooze sap once they begin to come out of dormancy. Which means that mid-winter is the best time. However, life is seldom perfect and there are times when you have to make a decision as to which is the best thing to do. Prune it or leave it.

I tackled this task of pruning the greenhouse vine in January. Leaving the vine – and therefore the greenhouse – as it was until late November would not have been a good choice. And because the vine had grown right across the doorway, some stems had to be removed to gain access even to tidy up.

If you’re not sure whether its too late in the season, you could make one or two cuts and see what happens. If the stem does bleed, the traditional method of cauterising what is effectively a wound (ie to stop the oozing) is to use a red hot poker.

Restorative or Rejuvenation Pruning

Restorative pruning, sometimes referred to as rejuvenation pruning or renewal pruning, is the removal of old, overgrown branches and stems to enable the plant to grow new ones. The aim being to restore or rejuvenate the plant to healthier growth by forcing it to renew itself.

To achieve this, plants may be hard pruned or pruned gradually. Which way the pruning is approached depends on, for example, whether the plant will tolerate drastic cutting back. Or indeed whether you would prefer not to lose all the fruit and flowers at once. Working on a three year plan is the one I’m following for pruning the greenhouse vine as this better suits the plant and my needs.

Pruning the greenhouse vine – How to Prune a Grapevine

The first thing to do before making pruning cuts – regardless of what you might be pruning –  is to look for dead, diseased and dying shoots. And remove those before starting on, for this vine, the first of the restorative winter prunes.

I’ve included the three short videos as it shows how to tackle ‘non text book’  grapevines. And I’m aware from teaching that this is what stumps gardeners the most – how to deal with the plant in front of them in their own garden.

Pruning the greenhouse vine

Rod and spur method of training grapevines

This dessert grape vine has previously been trained on a rod and spur method, which is the one most often used for indoor grapevines. It is sometimes known as the cordon method and can also be used for vines trained against an outside wall.

Regardless of whether you’re starting with a newly planted vine or dealing with an old one that’s run wild, the aim is the same. To encourage a multitude of fruiting spurs on short side stems growing from a main stem or trunk and side (lateral) stems / branches. (Yes the terms are interchangeable just to try and confuse you!) This gives you the maximum harvest, but also keeps the bunches in easy reach, as the overall height can be limited if required.

how and what to prune – greenhouse vine

What is a fruiting spur?

Grapevines produce fruit on new season’s shoots which arise from one-year-old stems. Now, although the vine will grow new stems and produce fruit on those, if the vine is left unpruned we end up with the wild tangle as I discovered here.

Put simply, developing fruiting spurs is really a method of training the vine to produce new shoots each spring where the new shoots are on short stems. In order to keep the vine productive, they need to be pruned to renew these productive stems and spurs.

fruiting spurs – how to find and prune

And finally

Of course pruning the greenhouse vine doesn’t stop there! My Border Collie Padme, aka head gardener, helped –

• find and prune back a honeysuckle that was growing through a broken pane of glass
• remove an invasion of ivy and disentangle it from around the vine
• discover a dog biscuit buried in the leaves (hmm)
• clear out all the fallen dead vine leaves, a couple of years’ worth I’m afraid to say