Weeds

Weeds present a significant threat to our natural vegetation. You can help by taking great care when choosing garden plants – especially if you are close to the coast or a natural area. For some ‘weedy’ plants (Gazanias or Fountain Grass for example) there are sterile hybrids available that will not become environmental weeds. Ask at your local nursery.

These are the weeds that present the greatest threat in Cottesloe at present.

Photos taken in Cottesloe by Robyn Benken – except where indicated. Information compiled by Robyn Benken from the following sources – Works Consulted for weeds (PDF 61KB, opens in new window).

Click on an image for a bigger picture (opens in a new window).

 Scientific nameCommon nameFamilyPriorityDescription
Acacia longifoliaSydney golden wattleMimosaceaeMediumThis garden escape is native to eastern Australia. A dense bushy shrub to 10 m tall with dark grey bark. The bright yellow flower spikes are cylindrical.
See more on Florabase.
Ammophila arenariaMarram grassPoaceaeLowA perennial grass, growing to 1.3 m tall which was introduced from Europe to stabilise dunes. It has been used successfully and disappears as other species grow higher up the stabilised dune. The leaves are stiff with rolled in margins and sharp points. Inflorescences are erect narrow spikes, greenish or straw coloured.
See more on Florabase.
Arctotheca calendulaCapeweedAsteraceaeMediumA very common plant from southern Africa. A rosette-forming annual with greyish deeply lobed leaves which are hairy white on the underside. Bright yellow flowers on solitary stalks from late winter to summer.
See more on Florabase.
Arctotis stoechadifoliaArctotisAsteraceaeLowA spreading prostrate perennial from South Africa, escaped from gardens into Cottesloe dune vegetation. The grey leaves vary in shape but narrow towards the base. The large singly held flowers are white, cream, pink or bronze. Flowering in August to December.
See more on Florabase.
Argyranthemum frutescensMarguerite DaisyAsteraceaeLowThis garden plant is salt and drought tolerant. It seeds prolifically and should not be grown near bushland in this area. A common weed in Cottesloe and Swanbourne bushland areas, having escaped from local gardens.
See more on Florabase.
Asparagus asparagoidesBridal Creeper or Florist’s smilaxAsparagaceaeHighThis South African plant is one of WA's worst environmental weeds. Birds eat the fleshy red berries and spread the weed. It is very invasive, dies down in summer then shoots rapidly and smothers other vegetation. A Weed of National Significance (WONS). Further information can be found at the WONS website.
See more on Florabase and Weeds Australia.
Asphodelus fistulosusOnion WeedAsphodelaceaeMediumA short lived perennial from southern Europe and India. The cylindrical leaves do not have an onion smell.The flower stalk is up to 60 cm tall and the white flowers have a brown centre stripe. An abundant weed near the coast.
See more on Florabase and Agric WA.
Avena barbataBearded OatPoaceaeHighOats are tufted annual herbs growing to 1.5 m tall. The inflorescence is drooping and one sided. Native to the Mediterranean and Asia.
See more on Florabase.
Carpobrotus edulisPigface or Hottentot figAizoaceaeLowA creeping perennial plant from South Africa which has naturalised. It has triangular succulent leaves which are often tinged red. Flowering in spring and summer and the large white or yellow flowers fading to pink. Fruits are eaten by birds, spreading the seeds.
See more on Florabase.
Chamelaucium uncinatumGeraldton WaxMyrtaceaeMediumA highly invasive weed which should not be planted near bushland outside its natural range.
See more on Florabase.
Chasmanthe floribundaAfrican CornflagIridaceaeMediumA plant with similar appearance to Watsonias. The flower spikes grow in winter to a height of 1.5 m, with orange or yellow flowers. Birds spread the succulent seeds. Originally from South Africa and now escaped from gardens. This plant should never be grown near bushland.
See more on Florabase.
Cynodon dactylonCouchPoaceaeHighA prostrate perennial with blue-green leaves spreading by rhizomes and seed. Widely planted as a lawn grass. It has invaded natural areas across Western Australia. Native to the Kimberley and tropical areas world wide.
See more on Florabase.
Dimorphotheca ecklonis (was Osteospermum)Veldt DaisyAsteraceaeMediumA woody perennial from South Africa which sends roots down from plant nodes. It is spreading rapidly in Cottesloe. The large daisy flowers in winter and spring are bluish-white or purple. Often growing locally as a garden escape or from garden rubbish dumped in natural areas.This plant should not be grown near local bushland or dunes.
See more on Florabase.
Ehrharta calycinaPerennial Veldt GrassPoaceaeHighA native of South Africa, a tufted perennial to 80 cm tall with drooping reddish-purple flowers. Flowering in Spring. A widespread weed of roadsides and sandy soils which when dry creates a significant fire hazard.
See more on Florabase.
Ehrharta longifloraAnnual Veldt GrassPoaceaeHighA South African native. A tufted grass growing to 30 cms tall. It flowers in Spring and has a greenish purple inflorescence (flower head). A widespread weed of coastal dunes and sandy soils.
See more on Florabase.
Euphorbia terracinaGeraldton Carnation Weed or False CaperEuphorbiaceaeHighA native of the Mediterranean and now a serious and common weed across Australia. A branching perennial which grows to 90cms tall and produces an irritating milky sap when cut. Flowering in summer with a yellow green flower head.
See more on Florabase and Weeds Australia.
Ferraria crispaBlack FlagIridaceaeHighA serious perennial weed of the Iris family. Spreading rapidly in Cottesloe. Native to South Africa. It is spread by corms, seeds and rhizomes. The lower leaves are sword shaped. Flowering in spring, the black ruffled flowers are carrion scented which attract flies.
See more on Florabase.
Freesia alba x leichtlinii FreesiaIridaceaeHighA popular garden flower which is now a serious bushland weed. It spreads by seed, off-sets and cormels. A hybrid of two South African species which flowers in Spring. This plant should not be grown anywhere near natural vegetation.
See more on Florabase.
Fumaria capreolataWhiteflower FumitoryFumariaceaeMediumA delicate annual with a twining habit and divided fine leaves. The spring flowers are white with reddish- purple tips. A native of Europe. It is spreading rapidly in Cottesloe’s natural areas.
See more on Florabase.
Gazania linearisGazaniaAsteraceaeHighA native of South Africa and a garden escape plant which is now spreading widely in coastal areas. A spring flowering, clump forming perennial with dark green leaves. The flowers are mostly yellow, orange and red. Only sterile varieties (available at nurseries) should be grown in local coastal gardens.
See more on Florabase
Ipomoea indicaMorning Glory or ‘Dunny Creeper’ConvolvulaceaeMediumOriginally from central America and has now escaped from gardens. A perennial vine with tuberous roots. The funnel shaped flowers are blue or purple. The vine can smother other vegetation.
See more on Florabase and Weeds Australia.
Lachenalia bulbifera Red SoldiersAsparagaceaeHighA robust bulb that produces many bulbils and also spreads by seed. A garden escape which flowers in spring. A native of southern Africa. It should never be grown near local bush or coastal vegetation.
See more on Florabase.
Lachenalia reflexaYellow SoldiersAsparagaceaeHighA native of southern Africa and now a serious bushland weed, spreading into good bushland areas. A garden escape which has naturalised in bush and heath around Perth. The yellow flowers in Spring are upright and on a very short stem. It produces copious quantities of seed and has bulbils on its leaves. These plants should not be grown in gardens anywhere near natural areas.
See more on Florabase and Weeds Australia.
Leptospermum laevigatumVictorian Tea Tree or Coast Tea-treeMyrtaceaeHighIntroduced from the Eastern states as a garden plant and to stabilise sand dunes but it is now a rapidly spreading major bushland weed. A shrub or small tree that grows to 4m. White flowers are borne mostly in spring and the leaves are green-grey. An invasive bushland weed now in the South African Fynbos.
See more on Florabase.
Lobularia maritimaAlyssum or Sweet AlisonBrassicaceaeLowA perennial herb that grows to 20 cms, a native of Europe and Asia with white or mauve petals. Widely grown as a garden plant and now escaped into sand dunes and bush locally.
See more on Florabase.
Lupinus cosentiniiWestern Blue LupinPapilionaceaeHighA widespread, serious weed from the Mediterranean. It has blue flowers on a short main stalk and produces much seed.The plant changes the soil pH and this has repercussions for revegetation efforts.
See more on Florabase.
Lycium ferocissimumAfrican BoxthornSolanaceaeHighA South African dense thorny shrub, growing to 3 m. It has fleshy leaves with mauve flowers. Birds are attracted to the red berries and spread the plant. Photo by Kaye Mc Lachlan.
See more on Florabase and Weeds Australia.
Mattiola sp.Stocks-LowSweet scented purple flowering stocks are a garden escape plant which are now growing well on secondary dunes in Cottesloe.
See more on Florabase.
Oenothera drummondiiBeach Evening PrimroseOnagraceaeLowA native of North America and Mexico that flourishes in WA coastal conditions. It can grow in drifting sand. A perennial with large bright yellow flowers which dies back in winter.
See more on Florabase.
Pelargonium capitatumRose PelargoniumGeraniaceaeHighA native of South Africa. A soft hairy shrub that grows to 1m high. The leaves are roundish and aromatic when crushed. The pink flowers mostly occur in spring and summer.The seed has a spring-like structure which assists it to twist into the ground.
See more on Florabase.
Pennisetum clandestinumKikuyuPoaceaeHighA lawn and pasture grass introduced from East Africa. It spreads by rhizomes and seed and is now naturalised in the wetter parts of WA.
See more on Florabase.
Pennisetum setaceumFountain GrassPoaceaeHighA native of Africa and the middle East which is unfortunately still being sold in some nurseries. Now a serious weed in bushland and spreading rapidly. A tussocky perennial with large feathery flower spikes which are reddish-purple. Flowering from March to August. Sterile ‘fountain’ grasses are available through good nurseries.
See more on Florabase and Weeds Australia.
Schinus terebinthifoliusBrazilian Pepper or Japanese Pepper TreeAnacardiaceaeHighNative to Brazil, the tree was introduced as a street tree and garden specimen. There are male and female trees. Red berries are spread by birds. It grows vigorously from roots when cut.
See more on Florabase and Weeds Australia.
Stenotaphrum secundatumBuffalo GrassPoaceaeHighA prostrate perennial grass that forms dense mats, planted as a lawn grass. Flowers in summer. Native to the Americas and Africa.
See more on Florabase.
Tamarix aphylla Tamarisk or Athel treeTamaricaceaeHighNative distribution in Africa, Mediterranean countries, India and China and now naturalised in Western Australia. Spreading by suckering and seeds. Able to tolerate salt (halophytic) and grows to 12 m.The summer flowers are pink or white racemes. A Weed of National Significance (WONS).
See more on Florabase and Weeds Australia.
Tetragonia decumbensSea SpinachAizoaceaeHighA succulent trailing herb from South Africa with thick pale stems and a very long tap root. A single plant can spread over several square metres of sand, smothering other plants. The leaves glisten with surface water storage cells. The flowers are yellow and the mature fruit is dark and leathery.
See more on Florabase.
Trachyandra divaricataDune Onion WeedAsphodelaceaeMediumA native of South Africa, now widespread in WA. The leaves look like onion leaves but have no onion smell, the plant is tuberous. The leaves are ribbon-like. In Spring the flower stalk is branched with white flowers. When mature the dry seed head rolls across the ground scattering seed.
See more on Florabase.
Tropaeolum majusNasturtiumTropaeolaceaeLowAn annual plant with sprawling stems and circular leaves. The spring and summer flowers are bright yellow, red or orange. A garden escape which now grows in bushland and along creeks. It is a hybrid originally from South America.
See more on Florabse.
Watsonia meriana WatsoniaIridaceaeHighSeven species of South African Watsonia have naturalised in WA, all garden escapes. They all have corms and stiff, upright sword shaped leaves, and spread by corms and seed. Watsonia meriana has dull orange flowers locally but they may be white, pink or cerise. It is a serious environmental weed.
See more on Florabase and Weeds Australia.