Woody Weed Specialists

A weed is any plant that is growing in an area that is shouldn’t be. However, there are a number of different classifications for a weed:

Noxious weeds – Serious problem weeds that are easily spread and are harmful to people or the environment. By law farmers need to control these weeds.

Weeds of National Significance – Introduced species that are highly invasive and have a big environmental and economic impact.

National Environmental Alert – Weeds that are introduced and are in the early stages establishing themselves that pose a threat to the environment.

Native plants considered weeds – These are weeds that while native to Australia, have extended beyond their natural range or habitat.

Weeds aggressively compete with any other vegetation in the area. They invade crops, harm livestock and can quickly spread across a property and prevent any productive use of that land for farmers.

Weeds will compete with other native plants or pasture for the three things they need in order to grow:

• water
• sunlight
• nutrients in the soil.

In any patch of soil there is only a limited supply of these three things, meaning that if the weeds are growing, they are stealing those growth inputs that would otherwise be used by the native plants in that area.

Typically weeds will outgrow the native species or grasses in an area because they:

• Are not affected by the pests or diseases that would limit their growth in their natural habitat.
• Are better suited to the growing conditions of an area outside their natural habitat.

This means that weeds on a property will inhibit the growth of Australian agricultural products, whether that’s a livestock farmer that is struggling to maintain pasture to feed and grow his stock or a wheat grower who is having trouble growing the crop.

The reason why weeds spread so quickly and grow so fast is because they have made their way into a habitat that is favourable to their growth, when usually there would be some environmental factors that would keep them under control.

When a weed enters an area it throws out the balance of that particular ecosystem, an ecosystem that has developed over many years and has achieved a balance allowing all the native species of plant in that patch of land to grow. Introduction of a new invasive species of plant that is more competitive and aggressive, means that the native vegetation that has slower growth or is more delicate, will be unable to continue growing and will die.

This effects not only the native vegetation but also any insect and animal species that relied on those plants for food.

African boxthorn is a woody shrub that can grow up to 6 m tall. Its rigid branches are leafy and end in a hard, sharp spine reaching up to 150 mm long. It has globe- to egg-shaped berries that are orange-red when ripe with up to 70 seeds. Flowers appear singly or in pairs at the leaf-stem junction. They are approximately 12 mm in diameter with five waxy white petals, each with a purplish base. The main flowering period is during summer but flowering and seed production may occur throughout the year.

Bathurst burr is an erect, much-branched annual herb, up to 1 m high but usually 30 to 60 cm. Leaves are dark green on the upper surface, a paler green on the under surface, up to 7 cm long and usually three lobed. Stems are branched with one or two three-pronged yellow spines at the base of each leaf stalk. Flowers are creamy green and small, developing into straw-coloured burrs, 1.0 to 1.5 cm long, with numerous yellow hooked spines. Each burr contains two seeds. Of the two seeds present in each burr, only one will germinate in a single season. The other seed will remain dormant for two or three years, sometimes longer.

• Blackberries commonly form dense thickets that may grow more than 2 m tall and cover large areas.
• The plant has prickly stems or canes that grow from a perennial crown up to 150 mm in diameter.
• The canes may be erect, arching or trailing and can reach 6 m in length.
• Leaves consist of three to five separate leaflets, are dark green on the upper side, whitish underneath, and usually bear hooked thorns on the leaf stalks.
• Partially deciduous it sheds leaves in winter.
• Flowers are 2–3 cm in diameter, white or pink in colour and are formed in clusters at the ends of the branches.
• Fruit change colour from green to red to black, each containing one seed.

Blue heliotrope is a perennial herb typically growing to about 60 cm in height. The plant has a large, well-developed root system. The leaves are lanceolate (tapering to a point) in shape, and can grow to 2–9 cm in length and 0.4–2.5 cm wide. They are a dull-green colour and are covered in short hairs.

Blue heliotrope has flowers that are arranged in a caterpillar-like formation, featuring 0–7 branches depending on the size of the plant. The flowers themselves sit in two parallel rows along small branches, with petals 5.5–8 mm in length. The flowers are purple to blue in colour, and can be found on the plant for most of the year, apart from in winter in more southern areas.

Cape broom (Genista monspessulana) is an upright evergreen shrub up to 3 m high, but more commonly 1 to 2 m. Young plants are capable of flowering and fruiting at approximately two years old. The leaves consist of three leaflets attached centrally to a short stalk. Leaflets have less hair on the upper surface than the lower surface.

Flax-leaf broom (G. linifolia) can be distinguished by its stalkless or near stalkless leaves, which have rolled edges and are densely hairy on the underside.

Cacti is not native to Australia, and most species are considered weeds in most states, some have become widely established invasive plants such as the prickly pear.
Other cacti weeds include:

• Harrisia cactus
• Prickly pear
• Snake cactus
• Smooth tree pear
• Tiger pear
• Tree pear

Camphor laurel is a large evergreen tree, growing up to 20 m tall. The leaves have a glossy, waxy appearance and smell of camphor when crushed.

In spring, it produces lush, bright green foliage and masses of small white flowers. The spherical fruits are 10 mm across, green at first changing to black when ripe.

Capeweed is a low growing, semi-upright plant, which means that the stems of the plant don’t grow straight up in the air, they grow out at an angle to the ground to form a rosette. This growth continues until the plant starts to mature and produce flowers, which tend to grow more vertically and can reach up to 30 cm in height.

Capeweed leaves are elongated in shape ranging 5–25 cm long and 2–6 cm wide, with each leaf broken up into tooth-shaped sections that run from the base of the stem to the tip. The leaves themselves can be slightly hairy on the upper surface, with a white felt-like underside.

The flowers are usually about 2–6 cm across with dark purple centres and numerous yellow petals.

Docks are exceedingly difficult to identify accurately in the vegetative (non-flowering) stage. Most species, including the commonly found curled dock, grow to around 1 m in height.

Docks are long-lived perennials and develop a deep taproot. They usually germinate in autumn and develop into rosettes through the winter. A flowering stem emerges in spring and the seed matures through summer. The stems usually die back during autumn and the plants over-winter as rosettes. The stems of the plant are relatively thick and hollow, usually hairless and somewhat fleshy in nature. The leaves of the plant vary in size depending on their position on the stem; however, they are usually arrow- or heart-shaped. The crown leaves at the base rosettes are typically 20–25 cm long with a rounded tip and base, while further up the stem the leaves reduce in size to become much shorter and narrower.

The flowers grow in clusters at the tip of the stem and each is made up of three small petals, growing on stalks typically around 5–6 mm long, while the fruit is a small three-sided nut surrounded by three papery segments.

Eucalypt appear in a variety of guises including shrubs, mallees and trees. Most, however, occur as forest trees of 30 to 50 m height or as woodland trees of 10 to 25 m height.

Bark types roughly fall into two categories. There is the persistent type, the ‘rough barks’ (e.g. stringybarks, boxes, peppermints and ironbarks), and the partly or wholly regularly shedding type, the ‘smooth barks’ (e.g. scribbly gums).

Fireweed is a member of the Asteraceae plant family. It is a daisy-like plant with endearing yellow flowers. It comes in a herb form and originated from South Africa. Fireweed has a variable growth habit and leaf structure, growing from 10 to 50 cm high. In coastal districts the most common form of fireweed is a low, heavily branched, short-lived perennial plant. Although leaf shape and structure can vary, leaves are generally bright green, alternate, narrow with serrated, entire or lobed margins. The broader leaves are usually clasped around the stem and are 2–6 cm long, occasionally reaching 8–10 cm on vigorous and older plants.

Fireweed has a shallow, branched taproot with numerous fibrous roots, growing from 10 to 20 cm deep. Petal numbers are usually a constant 13. Plants flower mainly from April to September, with individual plants often having a wide range of flowering stages at any one time. Seeds are small (1–3 mm long), light and slender. They are cylindrical in shape, with a downy surface and attached to a pappus of fine, silky white feathery hairs. The plant produces large quantities of seed over long periods that are easily dispersed by the wind. Each flower produces between 100 and 150 seeds. Long distance dispersal also occurs by seeds on animals, in stock feed or in mud on vehicles. The main issue to farmers is that it can outgrow most useful pasture plants. Fireweed also readily invades pastures damaged by overgrazing and drought. Fireweed seems equally at home in low-elevation, arid pastures as in high-elevation, moist pastures.

Gorse is a woody, deep-rooted perennial legume, capable of growing to 4 m tall. It has numerous small green leaves that form hard spines up to 5 cm long. Bright yellow flowers emerge in autumn and spring and plants produce large quantities of seed. The hard-coated seeds are spread up to 6 m by an explosive opening of the pods in mid summer.

Flowers are bright yellow, pea-like, approximately 20 mm long, and are borne all over the plant. The buds develop during February and March; however, flowering occurs in two distinct seasons, spring and autumn. Gorse seedlings can be eaten by livestock but mature plants have spines that can cause injury. Gorse is very competitive and reduces the productivity of pasture. Dense infestations restrict movement of livestock and provide a haven for rabbits and other pests.

Lantana is a heavily branched shrub that can grow as compact clumps, dense thickets and as a scrambling and climbing vine. The stems are square with small, recurved prickles along the edges. The leaves are bright green above, paler beneath, about 6 cm long, with rounded, toothed edges. Leaves grow opposite one another along the stem.

Flowers appear most of the year in clustered compact heads about 2.5 cm in diameter. Flower colours vary from pale cream to yellow, white, pink, orange, red, lilac and purple. Many lantana forms are poisonous to livestock. The toxic components in lantana include the triterpene acids, lantadene A (rehmannic acid), lantadene B and their reduced forms. Most cases of lantana poisoning occur in animals newly introduced into areas where toxic lantana grows. Animals bred on such country rarely show signs of poisoning.

Lime bush is a small tree with a dense, rounded crown growing to 8 m high. Young plants have long thorns on stems and branches. Bark is dark brown or grey, hard and deeply grooved; outer branches are smooth and grey. The leaves are a dull green, to 60 mm long by 5–8 mm wide; oil glands are obvious when held to the light; tips are rounded with a shallow notch. Leaves have a citrus smell when crushed.

Flowers are cream, with four or five petals, about 15 mm in diameter and sweetly perfumed. The fruit are round or oblong, 15–20 mm long by 15 mm wide, yellow when ripe, fleshy and dimpled. The flowering period is from August to October.

The lime bush suckers profusely and young plants form dense thickets. Fruit is edible and popular among the Australian bush food industry. Flowers are attractive to butterflies, bees, flies and wasps. Foliage is browsed by livestock and the fruit are eaten by sheep.

Lime bush occurs throughout south-western Queensland on heavy or light clay and loamy red earth. It is associated with poplar box, myall, silver-leaved ironbark, brigalow, belah or in open downs country.

Manuka is a prolific scrub-type tree and is often one of the first native species to regenerate on cleared land. It is typically a shrub growing to 2–5 m tall, but can grow into a moderately sized tree, up to 15 m in height.

It is evergreen, with dense branching and small leaves 7–20 mm long and 2–6 mm broad, with a short spine tip. The flowers are white, occasionally pink, 8–15 mm (rarely up to 25 mm) diameter, with five petals and seen from late spring to early summer.

Marshmallow is a semi upright weed that becomes more erect as it matures. It is characterised by rounded, wrinkled leaves with prominent veins, each consisting of 5–7 toothed sections. The plant stems are covered in stiff hairs, and produce pale pink or white flowers with five petals each, growing in small clusters in leaf forks or on the stalks.

Mimosa bush is a rounded shrub or small tree generally growing 1–3 m tall. It often forms thorny thickets, and is nearly always multi-stemmed. The branches grow in a zigzag shape and are usually a grey-brown colour with prominent white spots.

Leaves are a ferny type, with one to six pairs of leaf ‘branches’ each with five to 20 pairs of narrow, rounded leaflets 4–8 mm long. Leaves are sometimes more of a yellowish green than a pure green. Thorns are found in pairs at the base of each leaf and can grow up to 10 cm long.

The flowers are round, golden yellow to orange, about 1 cm across, and grow on stalks at the base of each leaf. Flowers develop into clusters of cigar-shaped pods, slightly curved and up to 6 cm long. The pods are dark brown or black and woody at maturity.

Mimosa bush can spread readily and grow quickly. It can be a considerable nuisance during mustering and can also hinder stock access to water.

Mother-of-millions are erect, smooth, fleshy succulent plants growing to 1 m tall or more. All species form tall flower spikes in winter with clusters of bell-shaped flowers. Each species has a distinctive leaf-shape but all produce small plantlets along the edges of the leaves.

These plantlets drop readily, develop roots and establish quickly to form a new colony. Of the three species naturalised in Queensland, two produce tall flower spikes in winter and have orange-red bell-shaped flowers that form in clusters at the top of a single stem. The third type, resurrection plant or green mother-of-millions, produces yellowish-green flowers, usually with a pink tinge that grow in clusters along the upper portion of the stem.

Plant material is poisonous to livestock; the flowers are especially toxic if ingested by grazing animals. Cases of cattle poisoning have been reported mainly during drought years when grass was very dry and other green feed unavailable. The main symptoms reported in cattle are scouring or straining, sometimes with evidence of abdominal pain and the faeces blood-stained or mucus-covered, with many affected animals dying after two to three days.

Noogoora burr is a short-lived, usually annual, shrub that is often abundant after spring and summer floods. It typically grows to around 1 m but may grow to around 2.5 m under ideal conditions and in the absence of a commonly-occurring leaf and stem rust and stem-boring and stem-galling insects.

The stems of the plant are rough to the touch, and feature short bristly hairs along its length. The leaves are usually a darker green towards the tips, and get paler as they get closer to the stalk. The leaves are covered in small bristles and are coarsely toothed around the edges, with three prominent reddish veins extending to each of the three lobes.

The burrs themselves grow typically to around 7–25 mm long and are covered in hooked spines.

Each burr contains two seeds. Seedlings are poisonous to stock and may cause losses if eaten in sufficient quantities, and the burrs are a costly contaminant in wool. Noogoora burr is a significant competitor in pastures and can be a serious weed in summer crops.

Paddy’s lucerne is an erect perennial weed that can grow up to 1 m tall. It is typically found in roadside areas and rocky terrains, although is also found in competitive pasture due to its unpalatability to livestock.

Its leaves are a dull green colour and diamond-shaped, 2–5 cm in length. The flowers are a pale orange to yellow colour and form on individual woody stalks and generally sprout in bunches of three or four.

The weed also produces a small fruit that is 30–40 mm long. When the fruit matures it separates into eight to 12 one-seeded segments.

• Parkinsonia emerges as a single thorny stem and matures into a thorny tree with numerous branches and slender drooping green stems.
• It grows to a height of 6 m and can form dense thickets.
• Leaves are very thin flattened rachises up to 30 cm long with tiny oblong leaflets in two rows along their length.
• Sharp thorns 7–12 mm long are present at the leaf nodes.
• Flowers are predominantly yellow but one petal either has orange spots or is completely orange.
• There are eight to 12 flowers on each inflorescence.
• The leathery seed pods are light brown when mature. Pods are 5–11 cm long, each containing two to four seeds.
• The seed-feeding beetle, Penthobruchus germaini, was released in 1995 and has reduced the amount of viable seed being spread.

Paterson’s curse typically grows to around 60–150 cm in height, often featuring multiple branched stems arising from the plant base. The stems themselves are covered in coarse hairs, as are the thinner leaves protruding from the stem.

The flowers on Paterson’s curse are predominantly purple, 2–3 cms long and shaped like trumpets, with two thin stamens protruding from the end of the flower tube.

Prickly acacia is a thorny shrub or small tree growing from 4–5 m to occasionally 10 m tall. The plants are distinct with fern-like leaves, a pair of stout thorns (1–5 cm long) and pods.

The young shrubs form dense thorny thickets and mature plants are usually single stemmed with spreading branches that have lost their thorns. The bark on saplings has a tinge of orange and/or green. Older trees have dark, rough bark.

The ball-shaped flowers are golden-yellow and about 1 cm across. The flowers grow in a group of two to six on a stem. The flat pods are 10–15 cm in length and turn grey when ripe.

Ragwort is an upright plant that grows up to 1 m tall. Each plant has numerous separate stems and each rigid branched stem is greenish-purple in colour. The leaves are deeply lobed, ragged in appearance, dark green on top and lighter underneath.

Ragwort flowers are daisy-like, about 1 cm across with bright yellow petals. The seeds are light brown, about 2 mm long by 0.5 mm in diameter and attached to a pappus of feathery hairs.

Mature plants have a crown just beneath the soil surface, from which numerous fleshy roots are produced. Ragwort is poisonous to grazing animals, with cattle, horses and pigs the most susceptible. Cross-bred sheep will eat ragwort without showing ill effects unless continually exposed to the plant in large quantities. Ragwort competes strongly with other plant species and will reduce pasture productivity.

Sifton bush, also known as the ‘Chinese shrub’, is a perennial shrub native to Australia. It has one main stem with multiple smaller stems branching off this. It typically grows between 1 and 2 m tall but has been known to grow to 3 m. Seedlings are quite erect and resemble tiny pine trees.

Silver-leaf nightshade (Solanum elaeagnifolium) is a deep-rooted summer-growing perennial plant from the tomato family Solanaceae. It is an erect, bushy plant growing 30 to 80 cm high. It reproduces by seed and from creeping perennial roots. Growth above ground from existing root systems appears in October or November. Plants flower from November or December to April and fruit is commonly set in February. Plants die back before winter but the dead stems with berries usually remain standing for a few months. The seeds germinate in autumn and the young plants produce an extensive root system in their first few months:

• Stems – erect, branched, densely covered in fine hairs and with numerous slender orange prickles.
• Leaves – silvery white underside due to dense cover of minute white hairs, alternate, 2.5 to 10 cm long, 1 to 2 cm wide, margins often scalloped; often with orange prickles on the veins.
• Flowers – usually purple to violet, occasionally white, commonly 2.5 cm in diameter but up to 4.0 cm diameter with five fused petals forming a shallow tube and five yellow anthers.
• Fruit – a smooth globular berry about 1.0 to 1.5 cm diameter, green with dark striations when immature and yellow and orange mottled and becoming wrinkled when ripe. There can be up to 60 per plan

St John’s wort is a perennial herb that can grow up to 1 m tall. It has stemless small leaves dotted with clear oil glands that have a perforated appearance when held to light. Stems are reddish in colour.

Flowers have five yellow petals, three bunches of many stamens. St John’s wort is widespread in pastures, water catchment reserves, forests and national parks and can cause photosensitisation in livestock.

It infests large areas of New South Wales, Victoria and South Australia and is a serious weed on tablelands and slopes areas as it is most suited to areas receiving more than 600 mm annual rainfall at altitudes of 600 m to 1500 m.

Swamp box is also known as swamp mahogany or swamp turpentine. It is a large tree with a red-brown, fibrous-papery, persistent bark. The leaves are broad and rounded at the base, tapering towards the end. They are 9–15 cm long and 4–5 cm wide, leathery, light green and either smooth or covered with soft, shaggy unmatted hairs. The leaf stalk is 10–20 mm long.

Clusters of white flowers 3–5 mm long are produced in early summer. The petals are circular, 4–5 mm long with numerous stamens.

Swamp box is widespread in sclerophyll forests and common in coastal districts, often on swampy ground or alluvial flats.

Sweet briar is a member of the rose family. A deciduous, upright shrub with arching branches containing backward curving prickles that can reach 3 m in height. It has an extensive shallow root system. Suckering occurs freely from the crown, and bushes often exceed 1 m in diameter at the base.

The leaves have five to seven oval leaflets, each with serrated edges. Pink to white fragrant flowers consist of a single row of five petals, while the fruit (hips) are bright red when ripe and often have bristles. Each hip contains many small yellow seeds.

Sweet briar is a perennial woody shrub that readily establishes itself in areas of moderate soil fertility where there is little pressure from livestock.

Thistles are erect flowering plants that typically stand around 2 m in height, with spiny leaves and stems. Early identification during the rosette stage of growth would ensure easer control options.

SCOTCH THISTLE

The flowers are made up of many small flower heads and are purple in colour. The stem and leaves on the plant are a whitish grey due to a fairly dense covering of short hairs.

SPEAR THISTLE

The flowers are purple in colour and made up of many little florets (tiny flowers), with spines on the stem and leaves. The stem leaves can grow up to 25 cm long and have a cobwebby texture.

SAFFRON THISTLE

The flowers can range from yellow to orange-yellow, and are surrounded by thin spiny offshoots that can grow up to 5 cm long. The leaves themselves are usually hairless, but can occasionally grow with hairs and the stems are hairless.

Wandering jew (Tradescantia fluminensis) is a highly invasive ground-growing, creeping succulent plant. This rapidly growing weed is generally found in areas that are moist and shady. It will out-compete native vegetation by smothering the ground using its roots sent out from each node.

The glossy leaves are dark green and oval-shaped to a point, growing between 5 and 10 mm long. This weed has small white flowers that have three petals and usually grow 7–10 mm long, with several bright yellow-orange pollen-covered anthers atop its stamens. The flowers are produced mainly in spring and are found in small clusters at the tips of brittle succulent branches.

Wandering jew has been found to cause allergic skin reactions in dogs and rapid death when consumed by cattle.

Wattles exhibit a range of foliage types. The true leaves are divided into leaflets; however, a large group of wattles develop modified, flat, leaf-like structures called phyllodes (which are simply flattened stems) soon after germination.

Foliage colour ranges from light or dark green to blue or silver-grey. Flowering can occur throughout the year, although the majority of species flower during spring and summer. Individual flowers are arranged in inflorescences that may be either globular heads or cylindrical spikes.