To mound or not to mound?

6
2973

Above: Thriving ten-year-old ghost gums in the Barry Bucholtz Bird-Attracting Garden, planted using Alex Nelson’s termite-attracting method. This photo taken in July 2018.

By KIERAN FINNANE

PHOTOS by ALEX NELSON

Planting into raised mounds is a good idea in places where drainage is an issue.

Not often the case in our neck of the woods.

Veteran observer of the local environment and noted green thumb, Alex Nelson, recalls the persistent failure of plantings into landscape mounds installed at the Olive Pink Botanic Garden in the 1980s.

Barren landscape mounds along the driveway entrance to the OPBG in July 2006.

He was employed at the garden in the mid-2000s, when the curator, Colleen O’Malley, had the mounds removed. Mr Nelson set to work, assisted by Phil Hosking, to demonstrate his own planting methods.

He prepares large holes, level with the surrounding ground. He backfills the holes with the excavated soil mixed with shredded paper (dry leaf litter or mulch also work). This stimulates a response by soil-dwelling termites, which quickly invade the disturbed soil to consume the paper and leaf litter.

The termites’ tunnelling activity creates structure in the soil, enabling air and moisture to penetrate deep beneath the surface (similar in purpose to earthworms, with which most people are familiar). The new plants respond positively to these conditions, enabling quick growth and increased drought hardiness.

Mounds removed, new plantings into flat ground, using the termite-attracting method, with shallow mounds to catch water runoff, June 2007.

“Others make paper out of trees, I make trees grow on paper!” says Mr Nelson.

The method’s success can be seen in the plantings that line the driveway entrance to the gardens and perhaps most spectacularly in two ghost gums planted in the centre of the Barry Bucholtz Bird-Attracting Garden.

They were planted by Ms O’Malley using Mr Nelson’s method.

“Their growth has far outstripped the growth rate of all other ghost gums – some dating from the mid 1980s – established by more standard methods at Olive Pink,” says Mr Nelson.

“In fact, it’s the fastest growth rate I’ve seen anywhere for this species.

“We’ve lost the Twin Gums west of town but now there’s a new pair at Olive Pink, rapidly established in response to a method devised in Central Australia and refined at the Olive Pink Botanic Garden.”

The spectacular display of Eremophilas and grasses one year on, June 2008.

The method is currently being used for the imminent planting of hundreds of new shrubs and trees at OPBG.

Below: The Barry Bucholtz Bird-Attracting Garden after one year, the ghost gums barely apparent, June 2008.

6 COMMENTS

  1. @ Evelyne Roullet (Posted December 14, 2019 at 3:19 pm): It turns conventional thinking on its head; termites are almost universally considered as pests within the context of gardening and horticulture, notwithstanding their recognised role as recyclers in the natural environment.
    I’ve simply found a way to exploit their behaviour to our advantage.
    By comparison, everybody these days considers earthworms as beneficial soil organisms but over a century ago conventional wisdom was that they were also considered to be pests and detrimental to agriculture.
    It was none other than Charles Darwin who overturned that notion after spending 40 years carefully studying earthworms. It was the topic of his last book (a bestseller) one year before his death.

  2. Thank you so much for this fascinating article.
    It seems to me this method would work in many places that have soils with low carbon and as a result low fertility.
    By digging a decent sized hole and mixing the original soil with dry carbon, there are many benefits:
    • Increased oxygen supply.
    • A food supply to attract critters.
    • The increased life underground keeps the soil open improving soil structure.
    • Any rain is absorbed deep into the soil.
    • Bacteria and fungi are awakened and proceed to harvest nutrients which will directly or indirectly be taken up by the plant.
    • The roots and travel through the soil as the structure improves.
    Win-Win.

  3. In answer to Evelyne’s query, I understand the new plantings program at Olive Pink Botanic Garden during 2020 (and ongoing) has proven outstandingly successful.
    It was (and is) the largest planting program undertaken in the garden’s history.
    Over 600 new plants have been established, with at least 550 installed with the termite-attracting method I first introduced there a dozen plus years ago.
    Late last year I was informed over 99 per cent have survived, an outstanding result.
    Very significantly, the work was undertaken by Aboriginal labourers – an apprentice employed by the garden and a team of workers from the Alice Springs Correctional Centre.
    They have achieved a result as good (if not better) as any landscape professionals.
    In my opinion it’s a highly appropriate achievement in light of the history of this reserve established by Olive Pink.
    It’s also in stark contrast to the usual story of the reluctance of Aboriginal people to be involved in horticultural work as typified in this recent report: https://alicespringsnews.com.au/2020/12/18/head-count-tourists-or-cattle/

LEAVE A REPLY

Please enter your comment!
Please enter your name here