Mulching Trees in Perth
Have you noticed in recent years the method of tree mulching in public places, especially parks? The mulch is deep and is spread right out to the drip tip of the tree (the ends of the branches).
Tree Mulching Effect
This has two main effects. The first thing and very important especially in traffic areas, the thick layer of mulch aids in preventing soil compaction. Soil compaction is responsible for poor drainage and aeration, definitely something to avoid around your trees. Secondly the thick layer of mulch insulates the soil against heat and wind. And then protecting the root area and keeping the soil underneath cool and moist. This in turn creates favourable conditions for ‘critters’ in the soil to do their thing and improve structure and fertility. It also means you will rely on irrigation less – if at all.
I recently came to the aid of a Jacaranda tree in a garden I was working on. It was in a fairly unforgiving area on a slight slope with no irrigation. The tree was stunted, had not flowered this year, was very light on foliage and the surrounding soil was rock hard. Rather than break my back trying to cultivate the soil I decided to let mulch do all the work. After some aerating with a crow bar I used a fine mulch, Greenlife® Mulch and Compost, to start with spread out to the drip tip and about 10cm in depth. I followed this with a 15cm layer of a coarser mulch, Course Pine Bark, and covering the same area. In between these layers I added several good handfuls of Organic Xtra Pellets and then watered this all well.
I came back two months later to inspect the results and noticed the mulch had settled down to half the depth, the tree had twice the foliage and on this 40 degree day in early January in Perth the soil underneath was moist and cool – still no irrigation.
I have taken some images in a park in the Perth. To illustrate the concept of this deep and extensive mulching method.
You can see how wide an area is mulched under this Lophostemon confertus (Brush Box). And there is also an image showing quite clearly the state of the soil underneath the mulch. These images were taken in mid-January 2009. When there had been very little decent rainfall for some time and the temperature had been in the high 30’s regularly. The site is slightly sloping and there is no irrigation but you can see that despite this the soil is moist and in good condition.
If you have trees that are not thriving and are convinced local conditions are conspiring against you ever succeeding in the getting them to grow this could be the remedy for you. It should be noted however that this method of mulching works well for trees but not for smaller plants like for example roses, perennials and smaller shrubs.