Weeds are great survivors. It takes more than a few years of drought and water restrictions to knock them on the head.
Indeed, weeds are lying low, waiting for rain and soil disturbance and ready to reshoot from underground bulbs, rhizomes or corms, or to sprout from seed.
Weeds come in all shapes and sizes, from small annuals such as petty spurge (once voted one of Victoria’s most annoying garden weeds) to large trees such as willows.
A plant’s weed status can vary within Australia and around the world. There are certain plants that are weeds the world over (such as thistles and dandelions), but others are plants that are nurtured in some gardens and weeds in another.
A good example is the flamboyant gloriosa lily (Gloriosa superba), which is the floral emblem of South Africa. Popular in gardens in southern Australia, especially as the large-flowered form ‘Rothschildiana’, the species is a weed along the north coast of New South Wales.
Even our floral emblem, the beautiful golden wattle (Acacia pycnantha), which is native to Victoria, is a weed in some parts of Australia.
To stay on top of weeds over the coming months, try to recognise and remove them before they get too large or reach flowering. Even if you can’t physically remove a weed, stop it seeding by removing its flowers by mowing or cutting them off.
If you find an unidentified plant in your garden, consider that it could be a weed – particularly if it is growing vigorously and you don’t remember planting it.
If you can’t get it identified while it is young, watch it carefully, especially as it starts to flower. Once it is in bloom, you or a neighbour may recognise it as a weed or realise it’s safe, as it is a desirable plant.
The weeds that give gardeners the most trouble are those with a support system in the form of an underground tuber, rhizome, bulb or corm. Oxalis, onion weed, morning glory and even lawn grasses, such as couch and kikuyu, that are invading our garden beds after the rain are all perennial weeds and difficult to control. Just pulling off their top growth won’t stop them from growing.
To effectively control a perennial weed like oxalis, kill the underground part as well as the bit up top. Use a herbicide that is taken into the plant and down to the roots, smother regrowth or try hand removal. Often all three methods are required, along with patience and a lot of repetition.
Once you’ve cleared a weed, make sure it can’t come back by covering the soil with a layer of mulch and by replanting.