Using the beneficial aspects of weeds has always been a core concept in organic growing. Organic growers use weeds to retain (sequester) nutrients when they would be leached from bare soil, to mine nutrients from deep in the soil profile with their penetrating roots, to protect soil from rain and runoff, to encourage good bugs, above and below the soil, with their pollen, nectar and root exudates, and to bestow the gift of carbon-rich organic matter.

These benefits are available in greater and lesser measure from a wide variety of plants. Sometimes native plants are completely able to provide these services, and there is also a role for introduced plants in environmental rehabilitation and much as in food supply.

We should also be aware of the potential harm from environmental weeds, and should act cautiously when balancing the benefits and issues around any particular plants species. In gardens or on farms, organic growers should be responsible to both neighbours and the environment.

My first serious job in horticulture was with a semi-rural local government where we did some rehabilitation of creeks and streams. My second professional job was with a quarry company, where amongst other things we rehabilitated mining sites. It was the early days of mechanical tree planting and direct seeding, and I saw a lot of failures.

On the best sites, usually fairly undeveloped pasture or old cereal cropping land, we could establish native trees with a high success rate. The more disturbed the site was, the lower the success with a standard choice of a few local wattles, a few local gums and a scattering of Banksia and other shrubs. Our disturbed sites might have rubble, sticky expanding clay, vegetation, and limey sand or trace element complications. Here we used a sequence of pioneering and succeeding plants to gradually re-establish a soil suitable for the longer-lived woody vegetation.

A range of endemic and Australian wattles and, in the harder sites, Casuarina, where our favourite choice, but in some sites we used grasses, creeping herbs and other herbaceous vegetation.

They weren’t meant to survive. They were just the ‘environmental pioneers’.

There is some potential harm from this technique, and some planning and careful consideration is called for. Each situation is unique, and important considerations are slope, aspect, climate, and the proximity of quality native vegetation or water assets, housing and susceptible agricultural enterprises.