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Weeds of Local Significance

african-olive-hz

African Olive

Olea europea
Evergreen tree 2 - 15m high. Drooping branchlets and narrow, dark green lance-shaped leaves, 5-10cm long and 2cm wide with a hooked tip. Younger leaves have tiny brown scales on the underside. White to cream tubular flowers, flowering in spring. Green berries in winter ripening to purple-black. Seedlings should be continually pulled by hand before they reach seed-bearing maturity. Unwanted mature trees should be removed with a chain saw. The final cut should be made as close to the ground as possible and as level as possible. That will make an herbicide application more effective and prevent resprouting from the cut. More information on African Olive at Weeds Australia.

asparagus-fern

Asparagus Fern

Asparigus densiflorus
Perennial shrub or scrambler, growing from thick tuberous roots formed on the rhizomes. Fruit is a red berry to 8 mm wide.Pull out or poison new infestations as soon as they are detected and before they flower. Check an infestation regularly over several years in case of regrowth from remnants of the root system. Dispose of any removed material carefully – root material can survive being dried for long periods, and seeds should not be composted or mulched. More information on Asparagus Fern at Weeds of Australia.

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Asthma Weed

Parietaria jucaica
Asthma weed, also known as wall pellitory or sticky weed is an environmental weed. The plant is spreading throughout gardens and bushland in the Sydney area and is declared a noxious weed. Asthma weed pollen may cause asthma, conjunctivitis, rhinitis and hay fever. Contact with the sticky hairs on the plant’s leaves and stem may cause skin rashes and other allergic reactions.

The weed thrives in cracks, particularly against wall. It is common on roadsides, gardens and especially where there is seepage. Asthma weed needs very little soil to grow and can tolerate sun, shade, salt, drought and frost. The weed is a many-branched perennial herb that grows up to 1 metre high. Leaves are green, soft, an oval shape with pointed ends, and are 2 cm to 8 cm long. Leaves are arranged alternately along pink or red stems. The plant is distinguished by irregularly curled hairs on leaves and stems; axillary flower clusters along much of the stem, stigma on a long style. Plants grow and produce seed very rapidly (within 2-3 weeks under favourable conditions). Regrowth is persistent and plants can flower and set seed most of the year. One square metre of asthma weed can produce 250,000 seeds. The seeds are dispersed by wind, water and by attachment to clothing and animals by sticky hairs. Seeds are also spread in soil and mud attached to shoes, tyres and machinery. Asthma weed can spread rapidly without control.

The plant can be controlled through either manual or chemical means. It is recommended that long clothing, a dust mask or half face respirator, eye protection (goggles or glasses) and protective gloves be worn when handling this weed. Manual removal includes pulling out the weed by hand, taking care to remove the entire root system to avoid reshooting. It is crucial to control asthma weed prior to seeding. It is important to place the weed in a plastic bag and then dispose of it, as opposed to putting it in the compost where it will spread again. Check clothing, tools and gloves for pieces of the plant to prevent further spread.  Follow up treatment will need to occur within three weeks of initial treatment, and may need to be repeated several times to eradicate this weed. It is helpful to mulch bare soils in an effort to reduce regrowth.  If roots are firmly caught in cracks in stone walls or concrete, herbicide may need to be used. Apply glyphosate-based herbicide to the plants while actively growing, and prior to flowering if possible. Spray the plants thoroughly for effective treatment.  All herbicide use should be undertaken with a registered herbicide as specified on the herbicide product label or relevant off-label permit published by the Australian Pesticides & Veterinary Medicines Authority. More information on Asthma Weed at Weeds of Australia.

Balloon Vine

Balloon Vine

Cardiospermum grandiflorum 
Climber with stems to more than 10 m long.  Plants have dense, usually rusty, hairy stems and flower stalks. Flowers 8–10 mm long. Fruit an inflated capsule covered with short stiff hairs. Large individual vine stems can be cut close to the ground and the basal stem cut painted with 100% Glyphosate (undiluted Roundup). Any vine seedlings can be successfully hand pulled or can be foliar sprayed if required. Balloon vine is not difficult to control and concentrated efforts can clear large infestations in a fairly short time. As with any weed species there is a need for follow-up maintenance and spot weeding to control newly germinated plants.More information on Balloon Vine at Weeds of Australia.

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Black Nightshade

Solanum nigrum
A fairly common short-lived perennial shrub 30–120 cm in height. Leaves 4-7.5 cm long and 2–5 cm wide, heart or oval shaped, with wavy or large-toothed edges. White flowers with prominent bright yellow anthers. The berry is mostly 6–8 mm diam., dull black or purple-black. Plants and seedlings can be easily removed by hand. Take care to not to spread fruit and seeds when removing this plant. All flowers and berries must be carefully removed and disposed of. More information on Black Nightshade at Weeds of Australia.

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Broad-leaf Privet

Ligustrum lucidum
Evergreen shrub or small tree to a height of 4–10 m. The bark is covered in small white spots (these are pores that allow gas exchange). Pointed oval-shaped leaves occur in opposite pairs, and are 4–13 cm long by 3–6 cm wide. The upper leaf surface is shiny dark green while the under-surface is paler with distinct veins. Cream or white tubular flowers are followed by berries that are green when young, turning red through to purplish black as they ripen. Controlling the spread of privet requires the removal of seed trees and young seedlings before they produce seed. More information on Privet at NSW Department of Primary Industries

Camphor Laurel

Camphor Laurel

Cinnamonum camphorum 
Evergreen tree to 20 m with a large, spreading canopy. The bark is greyish brown and has a rough texture. The leaves are alternate, 5-10 cm long and 2.5-5 cm wide and are a glossy green.The fruit is a round berry 8 mm in diameter, green when immature and ripening to black. Camphor laurel is easily identified by the pungent camphor odour arising from crushed leaves or exposed wood. Seedlings can be removed by hand or dug out with a mattock. Small trees (up to 10 cm in diameter) can be lopped and the stumps treated with glyphosate. Large trees should be removed by a professional arborist and the stump ground. More information on Camphor Laurel at NSW Department of Primary Industries.

castor-oil-plant

Castor Oil Plant

Ricinus communis
Shrub to about 6 m tall with large palmately divided leaves to about 50cm diameter when mature, objectionable smell of leaves when crushed and hollow stems. Produces a spiny, green seed capsule. Individual plants or small infestations may be removed by hand-pulling. Caution should be taken if removing castor oil plants manually given the high toxicity of the plant. Do not over-handle leaves as they can cause skin irritation. It is recommended disposable gloves be worn when handling this plant. More information on Castor Oil Plant at Weeds of Australia.

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Chinese Tallow

Triadica sebifera
Small to medium deciduous tree to 8m (25') tall with a medium domed crown. In autumn the mid-green leaves turn crimson, with some yellow, orange and ruby-red foliage. In November and December greenish yellow flower spikes appear on the tips of the branches, followed by 3-celled capsules. The fruit ripens and turns brown in autumn, then splits open to reveal three seeds which are covered with a layer of pure white wax. Seedlings should be continually pulled by hand before they reach seed-bearing maturity. Unwanted mature trees should be removed with a chain saw. The final cut should be made as close to the ground as possible and as level as possible. That will make an herbicide application more effective and prevent resprouting from the cut. More information on Chinese Tallow at Weeds of Australia.

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Climbing Asparagus

Asparagus plumosus  
Wiry climber to 5 m high on supporting vegetation. Fleshy berries green at first, ripening to black, 4–5 mm wide. Be sure to avoid dumping excess plants, berries or plant pieces in bushland. Unwanted plants should be dug out by the roots and disposed of in landfill. More information on Climbing Asparagus at Weeds Australia.

Crofton Weed

Crofton Weed

Ageratina adenophora 
Erect multi-stemmed perennial to about 2 m tall. Stems purplish. Roots thick, yellowish, extensive in mature plants. Seed brown to black, angular, 1.5–2 mm long, with a parachute-like plume of white hairs about 4 mm long at the top of the seed. Hand remove, taking all roots; bag flower and seed heads; do not leave stems on ground. Will reshoot if damaged. More information on Crofton Weed at NSW Department of Primary Industries.

fountain-grass

Fountain Grass

Pennisetum setaceum
Tall perennial grass forming tufts to 1m high. Thin, arching leaves 20-30cm long, with harsh texture. Flowers occur in purple, bristly, upright spikes at the ends of bamboo-like canes.Can be difficult to eliminate. Control may need to be repeated several times a year. Small infestations can be removed by uprooting, and removing and destroying seed heads. More information on Fountain Grass at NSW Department of Primary Industries.

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Green Cestrum

Cestrum parqui
Shrub to around 3m. Flowers are yellow and trumpet-shaped. The stems/branches are very brittle, they snap off easily. The leaves emit an unpleasant odour when crushed. Physical removal of all plant material is very difficult because of the complex root system but the plant will eventually give up if you keep at it.  For effective control of larger plants, scrape stems with a knife to expose the green layer beneath the bark and paint with undiluted glyphosate (round-up). More information on Green Cestrum at NSW Department of Primary Industries.

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Lantana

Lantana camara
A thicket-forming shrub 2-4m tall.  Ovate (i.e. tear-shaped) leaves 2-10cm long occur in opposing pairs along the stem. The leaves emit a pungent odour when crushed. Flower heads range in colour from white, cream or yellow to orange, pink, purple and red. Produces berries which ripen from green to shiny purple-black. Lantana is easily controlled in garden situations. Simply hand-pull or dig out – the root system is shallow and easily removed. Berries should be bagged and disposed of appropriately to avoid spreading the weed. More information on Lantana at NSW Department of Primary Industries.

madeira-vine

Madeira Vine

Anredera cordifolia
A climber with bright green, heart-shaped leaves. Produces tubers on roots and at nodes on aerial stems. Flowers are small, fragrant and white, borne in clusters. Plants propagate vegetatively by tubers. Can  grow as much as 1 metre per week in Summer and is very difficult to control. It will climb to the top of reasonably tall trees and is sometimes hard to spot unless it is in flower. To remove this plant it is best to scrape (15 to 30cm) with a knife along all accessible stems (and if a thick stem scape on both sides of the stem) and immediatly apply glyphosate. If stems are cut the tubers will continue to grow and will eventually drop to the ground and grow. More information on Madeira Vine at Weeds Australia.

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Morning Glory

Ipomoea indica
Twining vine with stems to more than 7m long. Leaves heart-shaped and sometimes three-lobed. Flowers pink to purplish-blue. This weed can be manually removed by pulling up the roots and mulching heavily to discourage regrowth. More information on Morning Glory at Weeds of Australia.

ochna

Ochna

Ochna sp.
Shrub to 2.5 m high. Leaves 2–6 cm long, shiny, with toothed edges. Fruit round, green initially, ripening black, and surrounded by the bright red petal-like structures (sepals), 8 mm long. Manual removal is difficult once a plant reaches only 10cm because when pulled it breaks off at ground level and then re-shoots vigorously. The most effective method of control is cut the main trunk as close to the ground as possible and immediately apply undiluted glyphosate (Round-Up). More information on Ochna at Weeds of Australia.

Pampas Grass

Pampas Grass

Cortaderia selloana
A tall grass growing in dense tussocks that can reach a height of 3m. The leaves are long and slender, 1-2m long and 1cm broad, and have very sharp edges (so they should be handled with care). The leaves are usually bluish-green, but can be silvery grey. The flowers are produced in a dense white plume 20-40cm long on a 2-3m tall stem. Manual removel of plants, particularly when small, is the best method of control in urban and bushland areas. This can be difficult with large plants because of their extensive root system and the abrasive nature of the leaves. Control of large plants is easier and more effective if any seed heads are removed first and the plant is slashed before digging out the crown and roots. Seed heads should be placed in a plastic bag and destroyed in an appropriate way. More information on Pampas Grass at NSW Department of Primary Industries.

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Panic Grass

Erharta erecta
An aggressive, perennial grass regarded as an environmental weed in New South Wales, Victoria and Western Australia. It is almost constantly in seed and develops large populations very quickly. It dominates the ground layer in native vegetation, restricting the growth and regeneration of indigenous plants and eventually eliminating smaller native species. It grows vigorously in open areas and is also relatively tolerant of sheltered, moderately shaded conditions. Remove all parts of plant including roots, if possible before it goes to seed. Take care not to spread seed to unaffected areas. Deep mulching is the best means of control in garden situations. More information on Panic Grass at International Weed Foundation.

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Red Root Amaranth

Amaranthus retroflexus
An erect, annual herb reaching a maximum height near 3m, usually smaller. The leaves are nearly 15 centimeters long on large individuals, the ones higher on the stem having a lance shape and those lower on the plant diamond or oval in shape. Produces a large, dense cluster of cream flowers interspersed with spiny green bracts. Hand remove, taking all roots. Bag flower and seed heads and dipose of appropriately. More information on Red Root Amaranth at Save Our Waterways.

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Rhus Tree

Toxicodendrum succedaneum
A small, deciduous tree 5-8 m tall with smooth grey bark. The leaves are compound, composed of individual leaflets which are bright green above and greyish beneath. In autumn they change to a brilliant red. Small cream to yellow flowers occur in large clusters in spring and early summer. Rhus may be mistaken for the similar looking Chinese pistachio which has similar leaves and is also planted for its brilliant autumn foliage. To distinguish them, note that the rhus leaf fronds end in a single leaflet while the leaf fronds of Chinese pistachio end in a pair of leaflets. Care must be taken when controlling Rhus as any contact with the tree is dangerous. Small plants may be dug out, taking care to dig out the entire stem to discourage suckering. When removing larger trees, remaining stumps need to be treated with herbicide to prevent regrowth. Clean all tools to remove sap, and  wear personal protective equipment  such as gloves, overalls, goggles, long-sleeved shirt and pants even when dealing with small seedlings. The risk of contact with sap can be reduced by waiting until after the leaves have fallen in winter before attempting to remove plants. Rhus branches should not be mulched or chipped for garden use. The toxic resin remains active for many months, even after weathering. More information on Rhus Tree at Department of Primary Industries.

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Tree of Heaven

Ailanthus altissima
A medium-sized tree to 20m. The bark is smooth and light grey. The leaves are large, compound, and arranged alternately on the stem. They range in size from 30 to 90 cm (0.98 to 3.0 ft) in length and contain 10–41 leaflets organised in pairs. The flowers are small and appear in large panicles up to 50 cm (20 in) in length at the end of new shoots. Tree of Heaven suckers readily. When removing a tree, the stump must be treated with poison unless excavating the entire root system is feasible, which it usually is not. More information on Tree of Heaven at Weeds Australia.

turkey-rhubarb

Turkey Rhubarb

Acetosa saggitata
A large non-woody vine with arrowhead shaped leaves, and small white flowers carried in long branched heads. Seed capsules are red, drying to brown, with a papery texture The plant grows from a conical underground tuber like a sweet potato. Constant re-sprouting from the tuber makes this species difficult to control. Plants can be dug up, but every tuber will need to be removed. Try to control vines before seed has formed but if fruits are present (even if they are still green), they should be collected and destroyed. More information on Turkey Rhubarb at Weeds of Australia.

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Wandering Jew

Tradescantia fluminensis
A perennial ground cover that spreads along the ground with soft, hairless stems and leaves. The fleshy stems root at any node that is on the surface. The plant has oval, dark-green leaves with pointed tips that are shiny, smooth and slightly fleshy about 3-6.5cm long. The flowers are white with three petals and approximately 1.3-2.5cm in diameter. They are produced in small clusters in summer but do not produce seeds. Manual removal can be is an arduous task since every  piece of the weed has to be removed or it will regrow. In less prolific areas, manual removal is less difficult as the plant roots come up easily, and an initial clearance can be accomplished by raking the area. Repeated efforts at intervals of a few months along with regular monitoring for invasion from neighbouring areas will be necessary for full control. More information on Wandering Jew at Weeds Australia.