The roots of large trees can be a problem if they grow out of control near the house or a busy driveway. Being able to manage the development of the root system without killing the tree is a complicated job that requires continuous maintenance; in many cases, the best solution is to kill the entire tree and replace it with another one with less aggressive roots.
Steps
Method 1 of 5: Kill Invasive Roots in the Ground
Step 1. Cut the least problematic roots
Although it is a challenging task, it allows you to manage the matter without harming the surrounding plants. Dig a hole around and under the first root, cut it out with a saw or pruning cutter. Aggressively cutting the roots causes the tree to gradually deteriorate and could kill it over the course of many years. Follow these general rules to prevent such damage:
- Multiply the diameter of the shaft by three. The value obtained corresponds to the minimum distance from the log in which you can cut without running the risk of causing serious damage.
- Cut the roots only on one side of the tree, especially if you need to cut them closer than the minimum safe distance.
Step 2. Dig a moat
Root trimming is only a temporary solution; to prevent them from spreading again, you must dig a ditch and cut them annually or even every six months if they are particularly aggressive. You can save yourself this work by digging a deep trench (at least as deep as the top layer of earth) and installing one of these barriers before refilling it:
- Galvanized sheet for roof cladding. Fold the top over on itself to avoid leaving the sharp and dangerous edge free.
- A double layer of HDPE, Overlap the sections of the barrier by at least 30 cm, so that the roots cannot creep underneath. that you sometimes find for free in grocery stores.
- For best results, purchase a specific root barrier that has been treated with herbicides; trifluralin is a product that is commonly used for this purpose and hardly kills surrounding plants.
Step 3. Kill the suckers with a herbicide
Some trees react to root cutting or other similar damage by developing new suckers from the root system. To selectively kill them, cut off the root so the chemical doesn't spread to the rest of the tree. Carefully apply the weed killer with triclopyr to the sucker, to avoid spraying it on nearby plants. Many plants that develop suckers grow a lot and quickly. If you don't want to kill the main tree, you need to repeat this treatment or periodically weed out the suckers by hand.
If you have cut down the main tree, but the suckers keep showing up, the only solution may be to spread a broadleaf herbicide; this substance kills all the vegetation present in the treated area. Repeat the procedure every time a sucker appears until the roots run out of nutrients
Step 4. Replace damaged flooring with gravel or mulch
It may be impossible to eliminate extensive root systems without killing the entire tree. In this case, you can lay a surface that the tree cannot overcome. Since this solution does not kill the roots, it does not protect garden areas or sewer pipes.
- Carefully remove all damaged concrete and avoid damaging the roots.
- Cover the area with geotextile, leaving the ground free around the trunk for a radius of 15 cm or for 30 cm, if the tree is large.
- Cover the surface with an 8-10 cm layer of inert gravel or with 15-20 cm of coarse mulch; the latter is less effective and could be washed away by the rain.
- Block the edges of the material with rocks to prevent it from moving.
Method 2 of 5: Remove Roots from the Sewer System
Step 1. Pour some copper sulfate or rock salt into the toilet
This is the simplest treatment, but it could kill the entire tree or surrounding plants. Flush one of the two products into the toilet (never in the shower or sink) in doses of no more than 250g at a time, until you have added about 1kg. Do not let the water run through the tube for 8-12 hours, so that the salt has time to kill the roots. Follow the safety instructions on the label.
Both of these chemicals cause severe damage to the aquatic ecosystem. Their use may be subject to restrictions in some regions or municipalities, especially in the vicinity of water treatment plants.
Step 2. Treat the pipes with a herbicidal foam
It is a product that expands filling the tube and slowly degrades; this feature makes it the most suitable solution for getting rid of the roots in the sewer system. Contact herbicides kill roots quickly, while systemic weed killers take a couple of weeks, but they could also affect the entire tree. There are different foams with variable consistency, based on the diameter of the tube; therefore read the label before proceeding with the purchase.
- Some herbicides are toxic to fish and wildlife; the instructions on the package should describe the environmental impact of the product, as well as some advice to minimize it.
- To obtain excellent results, appoint a plumber to apply metam-sodium: a corrosive chemical compound that can only be used by qualified personnel and with the appropriate safety devices.
Step 3. Have a professional clear the pipes mechanically
If the roots have completely clogged the ducts, they will also obstruct the passage of chemical treatments. Call a plumber to unblock the system with a specific tool. This solution also has the great advantage of having no impact on the environment, as is the case with herbicides.
Step 4. Repair the tube
Unless you want to repeat the treatments regularly, the now free tube needs some structural repair to prevent the roots from growing back inside. Installing a liner inside the duct requires less digging and confusion, but complete pipe replacement is often more economical.
You may have to remove or move all large trees near the pipe, or their roots will continue to grow in the sewer system
Method 3 of 5: Physically Remove the Stump or Tree
Step 1. First, do some research on the tree
Some species produce suckers, which means that a new trunk may sprout a short distance from the stump. Eliminating the trunk does not kill the roots, but it can even stimulate new growth. Avoid this technique for the species described below (this is not a complete list):
- Elm, cherry, plum and lilac can regenerate from the roots even after the trunk has been damaged; in these cases, you have to use herbicide.
- Poplar, aspen, sumac and locust which developed from "a colony of genets" during normal growth. The roots of these trees are very difficult to control even with herbicides. The department of agriculture of the municipality or the region can recommend an effective product for the species you need to treat.
Step 2. Reduce the trunk to a stump
If it needs to be felled, proceed so that only one stump remains 100-120 cm above the ground; in this way, the "stump" is large enough to give you a good grip to uproot it.
Attention:
cutting down a tree is a very dangerous job. If you don't have the experience and the proper tools, you run the risk of dropping it in an unexpected direction. If you've never done this before, trust a professional.
Step 3. Remove the stump
Dig the surrounding soil using a shovel, ice ax, jackhammer tip, or excavator. Cut off the largest roots with an ax or saw as soon as you bring them to light; remove all those that are around the trunk within a radius of 1, 2 m or until you find some main roots.
- Before using the chainsaw to cut a root, place a board under it to protect the tool from dirt and stones.
- When you've made some progress with the digging work, wet the area with a garden hose or pressure washer to bare the roots.
Step 4. Attach the log to a winch
Most tree stumps are too rooted in the ground to be able to be removed manually, especially if felling has taken place recently. Attach the stump to a hand winch anchored to a sturdy mast or use a chain attached to a van.
Step 5. Wind the winch slowly
Even a manual model is capable of eradicating a stump with such violence that it can fly dangerously through the air; slowly apply gentle traction to avoid this risk. If you have decided to use a van, drive it a little in reverse and a little forward alternately; in theory, the stump should gradually loosen from the ground and gently fall to the side.
Step 6. Flatten the stump if necessary
It is impossible to move very large stumps, not even with the use of a winch; in this case, you have to rent a stump grinder or entrust the work to a professional. This is a dangerous machine, so wear safety glasses and ask the rental company to show you its use. Here is the basic procedure:
- Get rid of any stones that surround the stump that could ruin the cutter.
- Place the sanding wheel a few inches above the front edge of the stump.
- Start the tool and gradually lower the cutter, making it penetrate into the wood for about 7-8 cm.
- Move the tool slowly to the right and to the left, removing the wood to a depth of 10 cm; repeat the procedure with the next section until you have smoothed out all the stump.
- Continue like this until the surface of the stump is at a depth of 20-25cm or more if you want to plant another tree.
Step 7. Fill the hole
Pull out any remaining roots and fill the hole the tree was in with soil. Sow some grass, water it, and you're ready to have a treeless patch that blends seamlessly with the rest of the lawn. Eventually, the roots should stop growing and decompose.
Method 4 of 5: Apply a Weed Killer to the Trunk or Stump
Step 1. Learn about the risks
The roots of trees belonging to the same species often grow together when they come into contact; this means that a substance sprinkled on a beech could spread through the root system and kill more beech trees in the same area. This phenomenon is quite likely with species that tend to form "genet colonies", such as the black locust.
Step 2. Choose a herbicide
Herbicides that contain triclopyr are very effective and you can buy them at gardening supply stores. The species present in the garden may be more susceptible to one product than another; for example, triclopyr is effective against black locust, maple, oak and willow, while other substances are more active with the Bohemian olive tree.
- Triclopyr should be effective in a concentration of 8.8%. Some also recommend glyphosate; it should be available in a concentration of 40% and must then be diluted with an equal amount of water or, if you find only the pure product, remember to mix it with water up to a concentration of 20%. There is a lot of debate regarding this herbicide which is subject to several restrictions, so gather a lot of information before considering its use.
- Herbicides that contain 2, 4-dichlorophenoxyacetic acid, dicamba or picloram are risky because they can spread to surrounding vegetation and kill it, which is not the case with careful application of triclopyr.
Step 3. Put on the safety gear
Follow the directions on the product label to avoid exposing yourself to hazardous chemicals. At a minimum, wear long pants and a long-sleeved shirt, closed-toed shoes, latex or nitrile gloves, and safety goggles; choose clothes that you can ruin without fear.
It is not necessary to use a mask, as it does not spray the herbicide into the air
Step 4. Pour the product on the log
This treatment prevents the development of all or at least most of the roots and the formation of new suckers after cutting the tree. It needs to be applied to a freshly cut surface, but if the tree has been felled for more than a few weeks, you should trim the surface of the stump to make a new one:
- Cut the stump close to the ground. Try to keep the surface level, to prevent the product from dripping onto the ground; it also eliminates all sawdust.
- Apply the herbicide inside the bark ring using an old paintbrush; in this area there are in fact the living tissues that carry the substance up to the roots.
- Throw away the brush and empty containers where the herbicide was at the hazardous waste collection center.
Method 5 of 5: Apply a Herbicide to the Trunk
Step 1. Kill the tree with a herbicide
It is a simple alternative to felling, although it may not be safe, as a dying tree could cause branches to fall on the road or driveway. Also, it may not be effective during spring, when the tree produces a lot of resin that prevents the substance from penetrating; however, if none of these situations represent a problem, apply the herbicide with a method that is based on the incision of the trunk:
- Cut the log in downward motions at a 45 ° angle to create a wedge opening.
- Insert the thin nozzle of a spray bottle into the gap and release some herbicide, making sure it does not come out of the cut.
- Read the product label to find out how many incisions you need to make and how much herbicide you need to apply in each of them (usually 1 ml is enough).
- With some particularly resistant trees you have to remove a strip of bark along the circumference of the trunk and apply the product on the wood below.
Step 2. Remove dead wood
After a few days or weeks, the trunk and roots begin to die and break apart; as the pieces of wood come loose, take them out and throw them away. When the tree has fallen or rotted completely, dig around the stump to uproot it, using a shovel or excavator.
Some trees or root systems need to be treated several times to let the herbicide penetrate the wood. If the tree survives, check the product label to find out how to apply more; remember to expose living wood to the substance
Step 3. Remove the stump
After the tree has died, dig around the stump using a shovel or pickaxe. Keep in mind that it may take years for the tree to decompose on its own, so it's best not to wait. Be sure to remove the stump completely to prevent the roots from growing back.
Advice
- To preserve the tree and keep it in good health, it is important to respect a good balance between the root system and the top. Cutting the roots close to the trunk (within a few meters) destroys up to a quarter of the root system. This is the reason why killing the roots usually kills the tree as well.
- To avoid future root problems, study the different types of trees that grow well in your region before planting them; it is also very important to know the root system of your tree. Some types of trees, such as maple and fig, are known to cause problems and are not suitable for burial near the house or along sidewalks.
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There are several ways to kill the roots or a stump, but they are too slow or ineffective to keep the roots in check:
- Remove a thick band of bark from the trunk to stop the nutrient supply from the leaves towards the roots. Killing a large tree with this method takes several years, unless a combined herbicide is used.
- Burying the roots around the trunk with mulch puts stress on the tree and makes it vulnerable; however, it takes several years for it to die.
- Burning a stump or burying it with compost or fertilizer are slow and ineffective methods.
Warnings
- Removing large roots from a live tree could cause it to fall off during windy days.
- Herbicides, especially concentrated ones, can severely damage the skin and lungs; if the liquid contacts the skin, follow the first aid instructions on the label.
- Some gardeners recommend pouring salt on the ground to get rid of the roots, but this also kills all the vegetation in the area, with the serious risk of also polluting the aquifer.
- If it rains within six hours of applying the herbicide, it is washed off.
