It’s important to keep the soil around the root system of mature trees free from traffic, caused by pedestrians and machines. This is especially important in urban landscapes, but it isn’t always possible due to where the tree is located.
In these conditions vertical mulching helps give the root systems much needed aeration and access to nutrients that are not always available, due to domestic gardening practises not being completed. Such as: clearing fallen leaves, regular collection of lawn cuttings and compaction of soil. All of which reduce air and water reaching the tree roots.
What is vertical mulching?
Vertical mulching is a process carried out by injecting pressurised air, via an air spade, into the soil surrounding the root system of a tree. This creates a vertical void in the soil between the roots. These voids are then backfilled with a mixture of grit, organic matter and slow release fertilizer. The voids of recompacted soil allows much needed air and water to the root system, while the organic matter and slow release feed gives the tree the nutrients its lacking in.
Hortlands recommend a large ring around the base of a newly planted, and a mature tree, if possible. The ring should be free from grass and compact soil. The ring should ideally be as large as the drip line of the tree canopy, as this will discourage pedestrian traffic over the majority of the tree root system. While also mitigating the need for lawn mowing equipment passing over the roots or damaging the lower hanging branches of the tree.