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Ivy - Friend or Foe ?

This is FAQ was compiled from several threads concerned with ivy on trees, walls and fences and whether it is detrimental or not. Also about removing ivy from walls and how to clean up the mess the tendrils leave behind.

I've tried to correctly attribute what was actually said, and cover all of the suggested remedies, but if you find a mistake or an omission, let me know.
To make finding the specific info that you want a little easier, I've highlighted the questions and indented the answers.


" I have a tree in the garden covered in ivy. Will this ivy damage the tree? "

Martin Brown replied: No. It does the tree no great harm, and looks nice and green in the winter.

Pete the Gardener added: If the ivy is just on the trunk then the only risk is that it can increase wind resistance, in high winds. This could potentially be a slight risk but I personally feel that it's worth it. However, if the ivy has grown up into the crown then it is possible that it could smother the tree. If the tree is not in the peak of condition for any reason, such as building work having been done near by or cable laying then the ivy could smother the tree and kill it. My advice would be to remove any ivy that looks like getting up into the crown of the tree but keep it on the trunk, it can look rather nice to see an ivy clad tree and its a very good habitat for a wide range of wildlife.

Caroline Lucas carried on the discussion with: We moved into a house last year with a large tree in, the trunk was covered in ivy from top to bottom, last year it had hardly any leaves and this year so far no buds have come out. I think the ivy has not helped the tree.

To which Martin Brown replied : But the tree was already on it's way out. Ivy thrives on dead and dying trees, but it does not kill them. My guess is you will find something else fundamentally wrong with the tree.

"And with regard to walls ........?"

Simon Jones asked: My father has an old property which is prone to dampness. There is Ivy growing on some of the outside walls and he is wondering if the Ivy will dry the walls by 'drinking' the water out of them or if it would have the opposite affect in increasing the dampness.

Nick McLaren is for: That can occur when the mortar is both soft and not too corrosive (e.g. the older lime mortars) and when the conditions are such that the wall remains damp for most of the year. If either condition fails, then ivy will do no harm to brickwork - it cannot get its roots into modern hard cement mortars, and will not grow roots into dry mortar. I doubt that it will dry out damp walls, but that is a guess.

Jon Rouse is against: Ivy and property don't mix. The roots get into the mortar, grow thicker and push the bricks out. Whole walls can collapse when the ivy is eventually removed.

Anton had a positive experience: This is just a single anecdote, which doesn't prove the case either way, but a few years ago I pulled quite a lot of ivy off a bay of my then house (built about 1900, softish mortar). The ivy was moderately recent- I would guess it had been growing there for 5-10years. There was no damage at all to the mortar or bricks. apart from some of the little hairy jobs still clinging to the wall & looking unsightly. I have to say that I find the idea that growing ivy up a wall might cure damp a bit unlikely. I suspect free air circulation from naked walls would be more likely to help.

Martin came back with : I hope - ivy on house walls won't by definition damage the walls. Ivy roots will seek out moisture, so if old, cracked mortar has allowed moisture in, the ivy may exacerbate the problem.

JennyC added that there are several advantages of ivy on walls : It adds an insulating layer for keeping heat in. It provides accommodation of birds and wildlife. It actually probably keeps the wall dry by keeping the rain of. It provides a climbing rack for other plants to scramble up.

Urban legend from Jon Rouse: I remember, when I was a child, a large Victorian house on the main road near us which had ivy growing up the gable end. They got contractors in to remove the ivy, and they cut through the main trunks at ground level, and then pulled the stems down. The whole top of the gable, attic window, slates and roof timbers, ended up in the front garden.

Yamxs850 wrote: It really depends on the condition of the brick walls. If they and the mortar are sound, ivy should not cause too many problems. It will make routine maintenance of the wall (e.g. repointing), very difficult to achieve, and may mask the presence of early signs of potential structural failure. If the walls and mortar are frail, ivy can damage them.

Jack Russel offered us his experiences with ivy: - Do not grow ivy on cracked walls, soft bricks etc., walls with soft mortar types, walls with weak foundations. - Keep ivy under control. Cut it back one or more times a year, remove shoots growing in unwanted directions, keep it flat on the wall. Overhanging ivy can cause a considerable loading. - It is very good for year-round covering of unsightly walls, for providing shelter to small animals, for protecting walls against rain. - If removed from a wall it will leave its footprints which are very hard to remove.

Consensus of opinion seems to be that :

Sound brickwork or healthy trees will be fine. Older property's with old cement might be affected.

The discussion was expanded with a further question.
"How can I remove the ivy easily?"

Sarah said: There is an easy way to remove 95% of the ivy from the walls, just leaving the little hairy bits behind, which should help you clear up your house. a) Cut through ivy stem at a convenient height, then grasp and firmly yank upwards, and hopefully a reasonable amount should come off ) This works really well. Tip : Get a length of metal pipe - copper pipe from plumbing the house should be fine. Cut a stem through, then slide the bottom of the stem into the mouth of the pipe, and then push the pipe upwards along the stem. when you've pushed as far as you can, give the whole thing a good upward and backwards yank to pull even more of the stem off the wall. This method works well because it leaves very little of the ivy on the wall.

Yearzero mentioned: There is also a proprietary root killer called RootOut, which I have often found necessary in the case of ivy.

Rodger Taylor commented: I found the easiest way was just to pull it off, starting at the top. With luck, it will come off in great intertwined sheets, especially if the brick has been painted. I wouldn't recommend killing the ivy first, as it will become brittle, making it harder to pull off in larger pieces. Further, killing it will actually harden the holdfasts, making them even more resistant to removing the largest of them later, with a paint scraper or sharpened heavy putty knife. Once you've peeled all the ivy off, you need to treat the severed basal roots in the ground with pure Weed be Gone, using a small brush, using it undiluted on the cut surface only, being careful not to pollute the ground around the cut off stumps. If you use an organic approach, you will need to dig the whole root system out, a fairly tough project. . . .

Jane Ransom offered a cautionary note: You have to be extremely careful. I know someone who chopped an ivy off at the ground and left it for a while. It nearly killed him when it finally fell, like a great blanket of intertwined stems, off the wall in one great mass !!

"How can I remove those marks the anchor roots leave on the brickwork ?"

Laura from New Orleans used paint stripper: I once had an ivy growing on my house: I thought it was beautiful, but it proved to be a catastrophe. My house was stucco and I had the hardest time getting the roots out of the wall.. It was horrible. I tried weed killer, chisels, everything imaginable. Finally, I used paint remover and it did the trick, because the roots are embedded in the paint. It worked and I hope maybe these thoughts might help you.

Sarah added: Let the remains dry off and go brown, and then use a wire brush to take the remains off - not recommended for flaky paint / plaster / pointing / soft bricks!

Jack Russel said: White wash the walls over the marks? Or introduce another climber :~))



FAQ compiled by JennyC on 13th January 2001

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