Finding out you have clay soils is not the end of the world. Here’s a few tips, tricks and proven techniques that will ensure you get the better of the clay and get better results from your soil.

Mike Gafa

 Revegetation projects on clay  018 Nursery

I always say, “You can’t plant a forest, but you can grow one.” In other words, revegetation success relies on thinking of the result you want to achieve as a long-term project, rather than something that can be achieved through a one off burst of planting enthusiasm and left to mature.

Goal one: Create cover. To protect the soil and reduce the need for weed control you need to create cover. Select fast growing plants to create an initial canopy. These canopy plants will support your project in a number of ways. Firstly, they create leaf litter through a constant process of defoliation (most NZ native trees are actually partly deciduous), which supresses the weeds and begins to work its way into the soil. This plant matter (known as duff) assists to break up and aerate clay soils and also contributes vital nutrients. Fast growing canopy trees include:

  • Pittosporum tenuifolium (Kohuhu)
  • Kanuka (Kunzea ericoides)
  • Coprosma robusta (Karamu)
  • Whiteywood (Mahoe) (Melicytus ramiflorus)
  • Five Finger (Pseudopanax arboreus) (Whauwhaupaku)


With the canopy established, your clay soil will improve by the day. For those of you who thought the role of a forest canopy was simply to provide shelter from above, this knowledge provides a much more holistic picture of how a sustainable forest environment works. And with the canopy established, bursts of planting enthusiasm are now not just appropriate, but positively encouraged.