Plenty of rain brings lots of garden weeds
How to cope with the exuberant crop of weeds brought about by last year’s happy flowering of nearby plants and trees without resorting to sprays is a challenge. While the soil is damp and the weeds are young most are easy to remove by hand. I have looked at three different situations:
- A garden in reasonable condition, which you hand weed then want to protect from new infestation.
- A weedy, perhaps neglected, garden where you are able to remove the source of the infestation but seed or bulblets remain in the soil.
- A weed infested garden where, even if you succeed with the current crop, a source of re-infestation remains nearby out of your control.
The first is by far the easiest. Remove the weeds, mulch well with material of your choice. Mulch conserves moisture, modifies soil temperature and eventually breaks down to add nutrients to the garden.
Courtesy of Gazette February 2012
Make sure it is thick enough so new weed seed does not penetrate. I have managed to keep a native garden weed-free for years just by throwing fallen eucalyptus leaves and broken-up bark onto it. The mulch has now stabilised at about 20cm deep and the native plants seem to love it.
You could then use live plantings to cover the soil. Gazanias form a dense mat. Erigeron, which can be invasive in mild climates, is an excellent solution where the going is really tough. Think also of the Mondo grasses, Ajuga, Spanish Shawl (Heterocentrons elegans), Liriope, Cliveas, Agapanthus. Mulch around the plants until they grow dense enough to discourage weeds.
The second situation needs more work. I have an Artarmon friend who took over a large neglected garden. Apart from annual weeds there was a heavy infestation of onion weed on which she tried the newspaper treatment with considerable success. Cover the soil with newspaper – at least 15 sheets thick.
Make sure the sheets overlap so light is completely excluded. Do not use any glossy paper. Top with your choice of mulch. Eventually the newspaper will break down and itself is added to the soil.
To plant new shrubs or trees, make holes in the newspaper. Afterwards pull the mulch back close to the stem of the plant. How long will this treatment last and will the onion weed eventually reappear? Possibly some will survive, perhaps some can then be dug out while carefully searching for and removing all the bulblets.
If you must spray, remember onion weed is most vulnerable when it is in flower, drawing down nutrients to feed those new little bulblets. Do not forget to protect your other treasures from the drifting poison.
The third scenario: It is pointless providing a lovely mulch of newspaper, etc if there is a continuing invasion of weeds from nearby.
Rampant weeds such as the Tradescantia ‘Wandering Jew’ will soon re-establish a foothold in your mulch although small rooted pieces left underneath the newspaper will, in time, be killed off. Try laying down weed mat then covering it with something that the weeds find positively discouraging – eg eucalypt leaves, casuarina or pine (conifer) needles. Any available mulch of this kind that does not break down quickly will do.
by Mollie Shelley