Your landscape from above may look beautiful and lush, but what happens underneath the soil is just as important. The root systems of your plant life, if not controlled, can cause tremendous damage to infrastructure, pathways and neighbouring plants.
Understanding invasive root behaviour and implementing proper containment strategies can save you thousands in repairs. Let's talk about the negative impacts of invasive roots and practical solutions to manage them.
Tree root systems vary depending on the type of tree. Some have shallow roots that spread far and even appear above ground, while others develop deep taproots that can burrow several metres below the surface.
Roots are constantly searching for nutrients and water to sustain the plant while also spreading out to provide stability. They move and travel depending on their needs and what is efficient for them, completely disregarding property boundaries or underground infrastructure.
The most problematic trees typically include willows, poplars, figs, eucalyptus and liquid ambers. These species are known for aggressive root systems that can extend well beyond the tree's canopy.
Roots that spread don't choose their path based on what is convenient for our homes, pipes and property. This often means poorly planned landscaping can lead to serious structural and financial consequences.
Here are the most common problems property owners face:
Water is one of the essential needs of life for humans and plants. Studies have shown that even water carried through pipes can attract the roots of plants through microscopic cracks or joints.
It doesn't fully matter if your home is properly built and irrigated. If potentially invasive roots are nearby, they will seek out your underground pipes and exploit any weakness to access that water source.
The repair costs for root-damaged infrastructure can be substantial. A single sewer pipe repair can run into thousands of dollars, while driveway replacement or foundation repairs can cost tens of thousands.
Our landscapes should be full of life, with various trees and plant varieties. But with these plants comes the hazard of their roots tunnelling to places they shouldn't.
The good news is you can have a beautiful garden and contain the root systems to where they need to be. One main method of containing roots are root barriers, which act as underground shields for your infrastructure.
Root barriers are made from high-quality polythene membranes and are placed either around the entire plant or just a single side. This depends on what areas need protecting from roots and the specific layout of your property.
The barrier is installed vertically underground, typically in a trench alongside driveways, buildings or pipes. When roots encounter the physical barrier, they are redirected downward rather than spreading horizontally into problem areas.
For larger commercial projects or trees with particularly aggressive root systems, this 600mm wide heavy-duty barrier provides maximum protection with its 1000 micron thickness to withstand the pressure from mature tree roots. The extra depth is essential when dealing with species like eucalyptus or figs near buildings.
For residential gardens and smaller trees, the 450mm option in the same robust material offers excellent protection for driveways, pathways and garden bed separation without the need for excessive excavation.
Proper installation is critical to the effectiveness of any root barrier system. Poor installation can leave gaps that roots will exploit or create barriers that fail under pressure.
Follow these key principles for successful root barrier installation:
The barrier should extend at least 50-100mm above ground level to prevent roots from growing over the top. This small lip can be hidden with mulch or soil for aesthetic purposes.
When installing root barriers, you'll need proper support stakes to maintain barrier positioning during backfilling. These 1500mm hardwood stakes provide the right height and strength to keep barriers vertical in standard residential installations.
Not all root barriers are created equal. The depth and material thickness you choose should match the tree species and the infrastructure you're protecting.
Here's a quick comparison of barrier depths for different applications:
| Application | Recommended Depth | Tree Types |
|---|---|---|
| Garden beds and small shrubs | 300-400mm | Ornamentals, small natives |
| Medium trees and pathways | 450-500mm | Crepe myrtle, small maples |
| Large trees and buildings | 600mm+ | Eucalyptus, figs, willows |
| Commercial and infrastructure | 800-1000mm | Any large species near critical assets |
Material thickness matters as much as depth. A 1000 micron (1mm) barrier is considered heavy-duty and suitable for mature trees with powerful root systems.
Cheaper, thinner barriers may save money initially but can be punctured by determined roots or degraded by soil conditions. Quality polythene barriers should last 50+ years when properly installed.
While root barriers are the most effective long-term solution, combining them with other management strategies creates a comprehensive approach to root control.
Regular root pruning can help manage existing trees near infrastructure. This involves cutting roots at a safe distance from the trunk every few years to prevent them reaching problem areas.
Proper tree selection is your first line of defence. Choose species with less aggressive root systems when planting near buildings or underground utilities.
For young tree plantings in areas prone to root spread, protecting the tree itself during establishment helps create a controlled growth environment. These large mesh guards in a 10-pack allow you to protect new trees from wildlife while establishing root barriers around the planting zone.
Watering strategies also matter. Deep, infrequent watering encourages roots to grow downward rather than spreading laterally near the surface where they're more likely to cause problems.
Creating designated root zones with barriers on all sides gives trees ample space to develop healthy root systems without threatening surrounding infrastructure. This approach works particularly well in urban streetscapes and commercial developments.
Don't let invasive roots take over your property. Understand that they can be very dangerous and costly if not dealt with, so it's important to get in early and take charge of your land.
Investing in proper root management now will save you significant expense and stress down the track. The cost of installing barriers is a fraction of what you'd pay for infrastructure repairs.
If you're looking to purchase this landscaping solution or you require installation guidance and more information, check out our root barrier range. You can also give us a call at 1300 130 123 and talk to our friendly, knowledgeable staff to assist you with all your invasive root concerns or other landscaping supplies.
