Why it’s important to cover-up quick
Plant out into the soil exposed by a digger as soon as possible. Bare soil will quickly dry out and be lost to wind or eroded by rain. Grass or clover will generally establish in spring or autumn if there is at least 100mm of topsoil or even loose subsoil.
Hydro-seeding is a good option, but you’ll need to hire contractors to pressure-spray the mix of water, seed, fertiliser, and paper mulch. It works well under ideal conditions, such as immaculately prepared ground at a new suburban subdivision. It can be more difficult on a block.
Hydroseeding was a complete failure at block owner Hazel Kidner’s property.
“All we did was feed the birds that autumn,” she says.
If it’s too dry or too cold to seed grasses, covering the soil with rotten hay is a good option, says GreenBridge co-director Bena Denton.
“You want to get those cuts covered as soon as possible.”
The hardest places to establish cover are the steep batters above tracks or building sites, which usually cut into the subsoil. For smaller areas where aesthetics matter, a batter can be faced with rock, as Bena and Daniel did on their driveway (pictured above).
Around house sites, digger operator David Bunn suggests creating a terrace halfway up a big batter.
“That will stop the water hooning down the batter when it rains. I prefer to go further back into the hillside (to create a shallower gradient). It needs to be possible to walk on the batter.”
It’s also easier to establish trees or plants on a terrace and creates a level path for access.
Use climbing, hanging or prostrate plants when re-establishing cover on steep faces. Bena has been experimenting with climbing fig, Ficus pumila. It roots at nodes and exudes a sticky substance that helps it cling to surfaces. It’s slow to spread, but thorough.
“I pick a spot where it will be bordered by a path or some other barrier to halt its roots,” says Bena.
Native Tecomanthe speciosa is another option. Once critically endangered, it’s
now widely available. Use in the right place, advises Bena, not where it can scramble over buildings or climb trees. She’s also trialling NZ jasmine (Parsonsia heterophylla) and cascading coprosmas.
Vetiver is another alternative, a noninvasive Indian grass with incredible soil-holding capacity. Its fibrous roots can penetrate 5-6m in almost any soil. Plant between September and March (it’s drought-resistant) but order early as vetiver plants tend to sell out quickly.