Ideas for community gardens < gardening

DEALING WITH INVASIVE GRASSES

Tips from Gavin Hardy, one of Brisbane's Northey Street City Farm crew...

One of the biggest headaches we Brisbane gardeners face is halting the spread of kikuyu and nut grass into newly established beds. Once these unwanted plants invade the garden they seem unstoppable.

We would all agree that the time consuming practice of sheet mulching provides only temporary control of these rapidly spreading grasses. Applying a herbicide can be effective but do we really want to be using these suspect chemicals around the home or community garden?

The less time we spend battling kikuyu and friends, the more we can enjoy the real delights of gardening. So, what are some effective, non-toxic ways of restraining the most ubiquitous of weeds?

Cover crops

As every good permaculture person knows, a cover crop of fast, low-growing plants can smother any of the shade-sensitive grasses.

Dense, broadleafed food plants such as sweet potato (Ipomoea batastas) and pumpkin (Curubita maxima) have worked well at the city farm's food forest at controlling kikuyu. Vgerous species like sweet potato, however, will take over a vegie patch.

Barrier planting

From talking to other city farmers and a lot of reading, it seems a combination of comfrey (Symphytum officinale), lemongrass (Cymbopogon edulis) and arrowroot (Canna edulis) surrounding each bed is an effective method.

Differences in root systems of these plants act together to form an impenetrable 'wall' at the garden's edge. Comfrey is deep-rooted, lemongraass forms matted roots, Canna roots are bulbous.

I have begun to trial comfrey and lemongrass to observe which subgle species is most effective, optimal spacing, establishment period etc. I am also trying out potential native species such as native ginger (Alpinia caerulea) and mat rush (Lamandra longifolia).

So, there are various types of plants which, if suitable placed, can be of great benefit in controlling kikuyu and nut grass.

The added benefits of providing food, green mulch and lowering fire risk in the garden are other reasons why these plants are of high utility.

If you're into pountry, the backyard chicken tractor is another multi-beneficial way of holding back kikuyu.

PAGE UPDATED... Wednesday, 16 January 2002