40 year old grapevine needs a new hoose!

[Fisherscot]

Hi all -- I have a bit of a crazy question, I hope someone can help! I bought a house two years ago and inherited this incredible grape vine, that someone trained through the lean-to wall. Last year it dominated the entire ceiling, and fruited, apparently even after being neglected for several years. This year, I've been pruning like mad and fertilising it.

The problem is that the lean to is rotting and needs replaced. The vine puts out loads of moisture on the inside and there's condensation. Lots of (crazy) people have suggested cutting down the vine and removing the maintenance problem. Other, equally crazy people like me, want to keep it and try repair the building around it.

My question is: How much can I do to make this a human-habitable indoor room before the vine is adversely affected? The builder is recommending 2 big 4x4ft Velux windows in a slate roof, with double glazed glass walls. So more like an orangery. Would the reduction in light and added insulation affect the vine? Could I add a wood burning stove? I really want to keep the vine but not spend a fortune building a room around it that I can't really use.

Any advice massively appreciated!!

[FB.]

Your fertilising will be making it grow even more vigorously, causing the need for more pruning. Unfortunately the fertiliser will linger in the soil for a year or two, so the vine will continue to grow strongly. But read on because you may have accidentally done a good thing......

Personally, I would do as little as possible with it until after all the leaves have fallen (around December-March). Then I'd cut it back very hard along the lines of a coppiced tree (retaining the trunk and a few feet length of its main branches - imagine just retaining what's in the bottom-left quarter of your first photo), then get your room rebuilt as required while the vine remains dormant, then next year train/prune the vine's new growth where you want it to go. There might be a lot of new growth and some regular 'tipping' or pinching of the shoots would help to guide it. You probably won't get much, if any, fruit next year though.

One thing about pruning old plants is that they usually won't tolerate hard pruning into older wood during the summer (pruning off green shoots in summer is OK); only hard-prune into woody shoots in winter when leafless - and even then it's best not to remove more than one-third of its mass (but you have to get your vine sorted in one go; I think it'll be OK as grape vines are tough, vigorous plants and yours has been well-fed in advance - the nutrients will be stored in its roots over winter for use next year).

[Fisherscot]

Hey FB, thanks for the reply! You're right, it's growing like crazy! Do you have any thoughts on the building around it? I'm looking to replace the greenhouse around it, maybe with a slate roof with big skylights and double glazing. Would that affect the vine?

[FB.]

The vine will grow where there is light. If you have a solid roof it won't grow across the roof (but it will want to grow across the windows - and maybe an 'espalier' shape would work for you).
I would have thought a PVC ('plastic') conservatory with carefully considered ventilation would be enough to prevent damp.

[Fisherscot]

That's interesting, so does that mean the top part of the T shape would only leaf under the roof windows?

The PVC greenhouse idea with proper ventilation would work, I just couldn't use it for sitting it or anything Seems like a lot of money for one plant!

[Fisherscot]

I just had to google "espalier", how cool is this?
File:Espalier fruit tree at Standen, West Sussex, England May 2006.JPG - Wikipedia, the free encyclopedia

Thanks for the replies btw, you're just down the road from me! I'm in Suffolk.

[veggiechicken]

Hi Fisherscot and welcome to the Grapevine! Seems very apt that your first post is about grapevines.
If you cut it back hard, could you train it up the outside of your Leanto? I realise that your crop of grapes will be less but designing a structure around a plant seems to me to be a bit OTT

[Fisherscot]

Thanks! You're not wrong there on it being OTT! I wondered last year about just taking the roof off but the expert I asked at the time said that it might kill the vine because of airborne fungi and things that it wasn't used to?

Check out what it looks like at the base, it's a monster! I'm not sure I'd be able to retrain it. My hand is there for scale on the inside and the other pic is the outside where it goes through the wall.

[FB.]

Apple espalier, several decades old:

[Fisherscot]

So, how do you train a vine to be espalier when it's already in an established T shape? I could see how cutting it back hard I could train the top branches to go in a different direction, but how would I get that layered effect when the trunk is already grown?

[FB.]

Thanks! You're not wrong there on it being OTT! I wondered last year about just taking the roof off but the expert I asked at the time said that it might kill the vine because of airborne fungi and things that it wasn't used to?

Grapes can suffer from some diseases, but I have one growing on the sunny wall of my house. Even though it gets what looks like a mildew on many of its leaves, it's still very vigorous and productive.
Chances are that over the 40 years since it was planted, some grape-disease fungal spores will have managed to get into your lean-to/conservatory and the grape evidently hasn't been bothered about it. I find that fruit tree seedlings get more diseases when grown indoors than outdoors because of the generally higher humidity indoors - which is showing in your decaying lean-to (fungi like humidity and warmth; a lean-to or greenhouse is perfect for fungi and diseases and you can't stop them getting in via draughts or even a gust of wind through an open door or window).

Change of climate would be the most likely problem, but if it has had a chance to 'harden off' properly it should be OK. By 'harden off', I mean wait until the risk of frost is gone (i.e. now) and remove your lean-to, then let the grape gradually adjust as the seasons change; it should adjust just fine, since plants have to be able to adjust to all the differences in weather from one season to the next.
It's sudden change in their climate in a matter of days that they don't like, especially going from warm to cool.

[Fisherscot]

That's really useful thanks, you guys have all been super helpful. I'm just trying to work out what the best thing to do with that area is now. The great thing I'm taking away from what you're all saying is that the vine is pretty tough and even if I take the roof off/add a new slate roof in etc, it will just adapt to its new surroundings. As long as I'm careful.

[FB.]

So, how do you train a vine to be espalier when it's already in an established T shape? I could see how cutting it back hard I could train the top branches to go in a different direction, but how would I get that layered effect when the trunk is already grown?

How about combining 'festooning' with 'espalier'?

-

[Fisherscot]

What a great diagram, sir! Heehee. I could see how that would work. Just need to make a decision on what to do with the building now...

[Printemps]

I reckon that your 40 year old grapevine is mature enough to stand on its own without the protection of your living space!

My own outdoor grapevine is of a similar age, perhaps even older, yet whilst I'm in the south west of France with plenty of sun to ripen the fruit, we do get temperatures as low as -14C in the winter. Vines are exceptionally hardy, indeed the delicious apertif/dessert and rather expensive ice wine is produced in Germany, Austria, Canada and Japan, where the grapes need to be subjected to at least -8C.

I had friends in Bury St Edmunds who trained a vine to form a 'living veranda', where they could sit within its shady interior in the summer and come the autumn, albeit with probably an extra jumper, could pick the grapes whilst remaining seated!

Do ensure that any pruning into old wood is only done whilst the vine is in its dormant period, other it will 'bleed'. I inadvertently left the pruning rather late one year and the cut into a rod of about 1" diameter dripped like a tap for nearly 2 weeks!

Do the know the variety of the grapevine? White or black grapes? For dessert or wine making?

If the conservatory has to be replaced then I'd ensure it was built for human use and confine the vine to the big wide world. With its established T structure I'd be tempted to erect a simple, narrow pergola on the outside - see attempted artistic impression - and retrain it!!



Bon chance!