11.3.1.Weed control methods

Manual methods such as hoeing plants out of the ground are the most efficient and direct for smaller invasions of environmental weeds, especially before the weed fruits or seeds.
If plants are too numerous or too difficult to remove, their seedheads or fruiting bodies can be removed by hand and destroyed to at least reduce spreading.
If that’s not sufficient, consider using plant competition to control weeds by maintaining healthy native pastures or sowing deep-rooted perennials along with tree revegetation, on degraded sites.
Council weed inspectors can advise landholders about the most suitable methods to control and destroy any noxious weeds found on a property.

Boxed section:
Willow alert
Willows have been planted along Australian waterways for many years and land managers have used them for erosion control.
Things have changed with the introduction of both male and female versions of aggressive hybrids — sold as fastgrowing windbreak, or stream bank stabiliser material.
Their prolific seed dispersal and ability to hybridise with a wide range of other species threaten major problems along rivers and streams in the Murrumbidgee Catchment.
Some of the problems caused by willows include their ability to out-compete other plants, block creeks and rivers, which alters water flow and causes erosion. Willows also take up large amounts of water (lowering water levels) and shade watercourses in summer, while in autumn their leaf fall lowers water quality.

Problem species
Willow seedlings have multiplied rapidly due to the introduction to Australia of both male and female plants of species such as the Black Willow (Salix nigra) and hybrid willows from New Zealand (S. matsudana x alba).
Other willow species that are causing problems include Grey Sallow (S. cinerea), Crack Willow (S. fragilis) and Basket Willow (S. x rubens — includes the species S. fragilis x alba and S. fragilis x alba var. vitellina).
A few species such as the common Weeping Willow (S. babylonica) do not produce viable seed and are considered by some to be less of a problem. However, female trees may be capable of crossing with males of another species, creating hybrids that may become major environmental weeds.

Keeping control
Willows have been declared a weed in NSW and landholders should avoid planting the female of the willow species within 300 metres of streams, rivers or farm dams (because of runoff). Some male willows also produce seed and it is difficult for the lay person to tell male from female willows.
A publication titled Willow management – a strategy for the upper Murrumbidgee catchment, 2010 collates past and present knowledge of willows and their management.
While it is specifically written about the Upper Murrumbidgee catchment area, the strategies discussed are relevant for the whole Murrumbidgee catchment.
Copies are available from the Upper Murrumbidgee Catchment Coordinating Committee online  or by telephoning (02) 62072999.
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