Ivy is famous for its ability to climb, whether on rocks, structures, or even other trees.
The roots of the word ivy come from a proto-Indo-European word that translates as “to grasp,” making it a very good and apt description of the plant’s tendency to take hold and go wild.
How does ivy work?
Ivy grows on the ground until it finds a suitable surface to climb. At this point, a surprisingly complicated process kicks into action. For many years botanists thought that ivy created a glue-like substance to attach itself to surfaces, but it actually goes a lot deeper.
Firstly, the plant comes into contact with the surface it will climb. Then, the roots change shape to fit the surface. At this stage, the roots aim to expand outwards as much as possible; increasing the amount of contact they have with the surface in question. Then, a glue-like substance is excreted, and small hairs on the root fit into tiny holes on the surface. When they dry out, they scrunch up and lock themselves firmly into the crevice.
With this process taking place many times on each surface, ivy builds a strong attachment that can be hard to dislodge. Because of the way the mechanism works, it keeps a strong hold even when the plant is dead, too, meaning that you can’t simply kill the plant and pull it down.
So, with that in mind, you may be wondering how to kill and get rid of overgrown ivy?
How to tolerate ivy
Let’s start with something a little less drastic. Here we’ll outline the times and places that ivy can be tolerated.
The first step here is busting the myth that ivy strangles the trees it grows on, hindering their ability to grow. It doesn’t. Unlike parasitic plants like mistletoe, ivy only uses trees for support, rather than penetrating their bark and leeching resources.
Ivy has its own root system beneath the ground, and gets the water and nutrients it requires from there. So seeing ivy crawling up a tree trunk isn’t an automatic cause for concern. Instead, keep an eye on things and see how they progress.
When ivy becomes problematic
If ivy starts to smother a tree trunk or prevent light from making its way through the canopy, it can be problematic. This can hinder the photosynthesis of the leaves whose light is being blocked, which prevents the tree from generating its required nutrients.
It can also be an issue when it comes to evaluating a tree for safety, as ivy can cover up structural damage, making it harder to see what’s going on underneath. If you’ve got ivy growing on an old tree that’s more prone to damage, you may want to consider removing it so that the tree’s health can be accurately assessed.
Ivy also has the potential to hold fungal spores that may cause damage to the tree underneath. Some rodents and pests shelter in ivy as well, leading to another potential source of strife for the tree.
How not to get rid of overgrown ivy
One thing you should never do is just grab ivy from a tree trunk and give it a good, hard yank. As we mentioned earlier, ivy has a very sophisticated means of attaching itself to surfaces, meaning that if you just grab and pull, it’s quite likely that you’ll strip some of the bark along with the ivy. Removing bark from trees exposes the tissue underneath, making it much more vulnerable to attack and infection.
If you’ve got ivy that you’re concerned is causing damage and needs to go, here are a few ways to remove it.
How to kill overgrown ivy
The steps for removal differ slightly depending on where the ivy is growing. In this section we’ll give instructions for removing ivy on walls, trees, and the ground.
Killing ivy growing on walls
We’ll start by emphasising that ivy doesn’t cause damage to sound masonry. This means that if your brickwork is in good condition, the mechanism ivy uses to cling and grow will not cause damage. If this is the main reason you’re considering removing the ivy, you may want to reconsider.
If not, here’s what you need to do –
Try non-weedkiller control methods first, as they’re usually more forgiving on the environment.
Cut stems back as close to ground level as possible, and dig out the woody stump at the base of the ivy plant. This isn’t always possible; it depends on where the ivy is growing. If you can’t get to it, trimming can help keep things is in check but is unlikely to kill the plant.
If this doesn’t work, sever the stem and use a weedkiller designed specifically for stumps and roots. Often these are based on chemicals like glyphosate or triclopyr.
Be careful when using weedkillers as the chemicals involved are very potent. There is an increasing amount of research into the dangers of exposure to glyphosate during pregnancy, for example.
When the ivy has been successfully killed, you can peel the plant from the walls and surfaces it’s grown on. Again, be careful as the tendrils are still anchored in fairly firmly. Pull gently and don’t be afraid to switch to a brush or scraper if needed.
Killing ivy growing on trees
The steps are largely the same, except with the caveat that you shouldn’t pull the dead ivy away. If you’re not concerned about the aesthetics of the dead ivy you can leave it on the tree, safe in the knowledge that it won’t cause any more problems.
Killing overgrown ivy on the ground
Ivy is an enthusiastic grower on the ground as well as up vertical surfaces. If you’ve got ivy crawling around at ground level and you’d like to keep it in check, here’s what to do –
- Dig up as many of the stems and as much of the root as possible.
- Take a look at the weedkillers mentioned above, taking special care not to let other plants come into contact.
- You can ruffle the ivy leaves with a rake or similar tool to damage their surface, giving weedkiller more of an opportunity to soak through (the leaves in their natural state are quite lacquered, making them fairly resistant to moisture).
- If the ivy is growing in a spot you’re not planning to use for growing other plants, you can cover it over with carpet or a thick layer of bark mulch for a couple of growing seasons. This will prevent the plant from getting the sunlight it needs to survive, ensuring a slow but certain death.
Salt water and duct tape
One method for killing ivy that you’ll see mentioned fairly often is to slit the root, then use duct tape or similar waterproof tape to create a cone-like structure around it. With the slit contained you can pour saline solution (water + salt) into the cone, which will gradually enter into the root system and damage the ivy. Simultaneous and repeated applications of this treatment can eventually kill the plant.
The antisocial climber
If you’re facing an onslaught of ivy on your home, a tree in your garden, or anywhere else, hopefully this guide has shed some light on the potential solutions available to you.
One of the most important things to keep in mind with ivy is that often, it isn’t causing as much damage as you might initially think. The common misconception that ivy strangles trees and drains their nutrients, for example, is wrong. As we said earlier, it gets moisture and nutrients from its own root system, and only uses the bark as a foothold for climbing.
It’s the same with ivy on buildings: its presence doesn’t automatically signify damage or cause for concern. It’s only if ivy is growing on masonry in poor condition, or if it’s threatening gutters or similar accoutrements.
So, if you’re considering killing ivy, take a step back first to evaluate whether it’s really the best course of action. Then, once you’ve done that, try to prioritise solutions that don’t require weedkillers. While these chemicals are effective at removing weeds, they’re also fairly good at causing wider damage to the environment and should be avoided where possible.
Whichever method you go for, we hope that this guide has been useful in helping you to conceptualise the problem and find the right answer.