As the southern hemisphere turns to face the sun, it is peak season for colourful wildflowers, exotic annuals and native shrubs.
asserted
it → turn → wildflowers
Lawns, garden beds, and every nook and cranny with a patch of bare earth are relentlessly colonised and overrun by a familiar line-up of botanical pests.
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Lawns → colonise → pests
Others, like the dreaded bindii or bindi-eye, are a literal pain.
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Others → dread → bindii
What weeds say about your soil
The adage suggests weeds offer a helpful insight into soil health.
uncertain
weeds → say → health
ABC Local Radio gardening expert Rob Pelletier from Heritage Fruit Trees said that was only partly true.
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that → say → Trees
"Certain weeds favour particular conditions, but they are not a reliable soil test and they are not necessarily 'repairing' the soil,"Mr Pelletier said.
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Pelletier → favour → conditions
A better idea, he said, is to create the best possible growing conditions for the plants you want and avoid leaving bare soil for weeds to take hold.
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weeds → say → hold
Herbicides can control weeds, though many have side effects that make them less attractive for some gardeners.
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them → control → gardeners
Two non-chemical methods Mr Pelletier recommends involve sunlight, albeit in opposite ways.
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Pelletier → recommend → ways
Occultation involves covering weeds with an opaque object, such as a tarpaulin, to block the light they need to photosynthesise and grow.
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they → involve → light
Solarisation, on the other hand, uses sunlight and clear plastic to heat moist soil.
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Solarisation → use → soil
This has an even greater effect on weeds, weed seed, pathogens and soil organisms, as it heats the soil and cooks the weeds.
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it → have → weeds
Beyond the garden fence
While weeds can be a constant irritant for gardeners, they become an even greater problem when they escape the garden fence.
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they → become → fence
Gazania, introduced as a pretty ornamental flower from South Africa, shows how a species can become an environmental scourge.
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species → introduce → Africa
Environmental scientist Kate Blood, a former weeds management program manager with the Victorian government, says the damage they cause is immeasurable.
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they → say → government
"In native grasslands and woodlands, gazanias crowd out indigenous plants that provide essential habitat for wildlife,"she said.
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that → crowd → wildlife,"she
"They are also becoming a serious problem for farmers, spreading into paddocks and cropping land.
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They → become → land
Researchers are searching for practical, affordable and effective ways to manage them.
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Researchers → search → them
Ms Blood says weeds enter your garden or lawn in a variety of ways, but once they become weeds, little can be done.
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little → say → ways
"Ever had a random new plant like ivy or lantana pop up in your garden?
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plant → have → garden
Chances are its seeds were carried there in bird droppings or arrived through one of the many other ways plants spread — on the wind, in water, on clothing, animals or vehicles," she said.
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she → carry → clothing
"This is how invasive garden plants escape beyond the backyard, finding their way into bushland, waterways and native grasslands.
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plants → escape → bushland
"What you plant in your garden can have a profound and lasting impact on nature around you, even if you live in a large town or city."
Ms Blood is the Weed Society of Victoria president.
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Blood → plant → Victoria
Her advice to reduce the spread of weeds in the first place is:
- Replace invasive garden plants with safer alternatives.
- Select garden plants carefully, checking their weed potential before buying or planting.
- Dispose of garden waste responsibly to prevent invasive plants spreading beyond the garden fence.
"A beautiful garden shouldn't come at the expense of the natural environment around it," she said.
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she → reduce → it
Colonisers, exploders, and persistent perennials
There is no one-size-fits-all solution for the multitude of invasive weeds that pop up during spring.
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that → be → spring
Many could be classified into three groups, said Mr Pelletier, each with a different control strategy required.
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Pelletier → classify → strategy
"You can look at colonisers which exploit bare or poor ground," he said.
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he → look → ground
"Then there are annual weeds that suddenly explode into growth and seed.
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that → be → growth
"And there are your persistent perennials, which keep coming back from underground parts."
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which → be → parts
Colonisers
Colonisers are weeds that thrive where desirable plants are struggling, or the soil is bare.
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soil → thrive → ?
Spring exploders
These are weeds that often germinate through winter, then grow and seed rapidly during spring.
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that → germinate → spring
Control: Hoe or pull them while small and, most importantly, before they seed.
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they → hoe → them
Persistent perennial weeds
These weeds survive through bulbs, rhizomes or deep roots, so simply removing the tops rarely works.
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removing → survive → tops
The Aporia