Pruning is a very common chore that both experienced and inexperienced gardeners undertake each year. Pruning and lopping can both be extremely good for your trees, if you do the job the right way, at the right time. Your trees end up thriving, with fresh, new growth appearing where you want it. Did you know though, that pruning, or lopping doesn’t only include trimming branches, but also roots? That’s right – you can trim your tree or shrub roots when they are still saplings and even when they are a bit older, if you’re careful.
Just like with pruning, you need to know what you’re doing and be very careful, as doing it the wrong way can cut off your tree’s ability to access water, weaken their anchor to the ground, make your tree sick or worse, even kill it. Doing it the right way can yield many benefits though, such as:
- To stimulating root growth
- Create root density for a stronger and not resilient tree
- Increase fibrous growth of roots, which increases nutrient absorption.
- Facilitate potting by reducing the size of the root ball
- Enable repotting of a root-bound plant in a new pot
- Removed damaged or diseased roots
- Slow growth of a plant (energy goes towards regrowing roots, rather than top shoots)
- Used to create bonsai (this is a specialty root cutting technique called root training).
- Remove invasive roots from an area you don’t want them to grow
To ensure your tree isn’t harmed during root pruning, there are a number of things you can do or consider. Firstly, make sure all your cutting tools are wiped with an antiseptic solution
(hydrogen peroxide is good for this). This will prevent your plants from getting an infection. You also need to be aware of the size and location of the root you want to prune, determine how much you should cut and what time of year to do it in.
Air Pruning
There’s no problems with trimming the root systems on saplings or transplant trees that have not yet taken root, but this should be done in a particular way. It’s much more difficult to do once they’ve properly taken root; however, you can prevent any future problems with root bound plants by ‘air pruning’ or ‘light pruning’. Air or light pruning works on the principle that tree roots do not usually grow aboveground due to their sensitivity to light and air.
You can therefore actually create a situation where a tree will prune itself utilising these mechanisms. It involves planting trees in fabric pots or white grow bags whereby the roots – once reaching the outer fabric – will not grow past it because of the sunlight and air. Instead of the universal black pots that most people are accustomed to using, the white bags allows the light to penetrate the bag and expose the roots once they hit the surface, which makes them stop growing or slow their rate of growth dramatically.
Methods of keeping your plants healthy during pruning
Sometimes – despite using air or light pruning – the roots may grow too large and protrude from the fabric anyway and you will need to manually prune them; however, you first need to check if the plants have become root-bound. If this has occurred, it definitely needs to be rectified; however, this should only be done very rarely (every two, or even better, three years) as trees can go into shock if it’s done too often!
If you’ve determined that your tree is root-bound, the first step is to turn the pot upside down and remove the plant without any (or at least minimal) force by lightly shaking it. You can use a butter knife to wiggle down the side of the pot and relieve some of the tension until the plant releases from the side, if your plant is stuck. Once you’ve released the plant, use some sharp pruning shears to trim around the outer roots, then loosen the surrounding soil.
When you’re pruning, make sure you don’t cut the corm, bulb or taproots – only cut the feeder roots. If the root situation is especially unkempt, it can be a good idea to carefully cut the interior feeder roots. When you’re pruning, you also only want to take – at the absolute most – two-thirds of the roots; it really shouldn’t be that much though. Once you’ve gone through this process carefully, then its time to re-pot. It is a very traumatic event for your tree, so make sure you perform it in the shade, keep it in the shade during recovery and a high level of watering and other aftercare is needed.
For part two of our article, see ‘You’ve Heard Of Pruning, But What About Pruning Tree Roots Pt2’ to learn the next steps. If you have any issues with the roots of the trees on your property though, give Brisbane Treeworx a call on 0400 249 099 or click here.
