Originating from South Africa, African Boxthorn is a fast growing invasive species that, if untreated, spreads quickly. It reproduces exclusively by seed which is commonly eaten and then spread by birds. If untreated, African Boxthorn grows to a great size and dense infestations out-compete native plants.
Caltrop grows flat along the ground, stemming from a central tap root to about 1m long. Leaves are oppositely arranged and flowers are yellow. Flowers then turn into woody burrs with sharp rigid spines which split into five wedge-shaped segments when ripe. If discovered it must be reported to local Council for professional removal.
Common Evening Primrose
Evening Primrose is native to South America and is regarded as an environmental weed in South Australia. It produces yellow flowers and is most abundant in coastal locations, especially in sandy soils.
Dune Onion Weed
This weed's fleshy leaves spread over the sand surface and are up to 1m long. It reproduces by seed; as the wind dislodges and carries crowns of mature infloresences acting as tumbleweed, it spreads numerous small fine seeds which eventually displace native species. At Taperoo Dunes we report the weed to NRM and flag it with pink tape for professional removal around September/October.
Euphorbia is one of the weeds which we most often come across at Taperoo Dunes. It grows up to 1m high and spreads quickly forming dense patches, displacing native plants. The stems contain a milky sap which can irritate the skin and eyes so it is important to always wear gloves when handling this plant. ‘False Caper’ refers to its resemblance to the true caper (Capparis spinosa) and the name ‘Euphorbia’ after the Greek Physician Euphorbus who discovered its apparent medicinal uses!
Gazania, from South Africa, is a highly invasive tough perennial herb growing vigorously in coastal sands and dunes and capable of withstanding salt-laden winds. It has brightly coloured yellow daisy flowers with a dark ring in the centre. It can form a thick carpet smothering other plants and it also sucks a lot of water from the dune profile. It reproduces vegetatively and also by producing abundant wind-blown seeds which contribute to its spread.
Sea Spurge can grow up to 70cm high with several erect stiff stems and is native to Europe, Africa and Asia. It spreads rapidly and invades coastal areas, displacing local species and colonising open sand areas favoured by certain nesting birds. It can also change the shape of foredunes, exacerbating dune and beach erosion. Its milky sap is toxic and can irritate skin and eyes.
Skeleton Weed is native to Europe, Asia and North Africa and belongs to the daisy family. It is a thin, spindly plant which grows up to 1m and produces small daisylike flowers. It successfully competes with other plants for water and reproduces by seed and also by cloning itself at the root, so chopping up the plant will actually help the species disperse by distributing the root parts.
A native to Europe, the species name 'calcitrapa' comes from the word 'caltrop' due to its sharp spikes. A drought tolerant plant, it grows to around 1m high and forms dense masses of growth displacing native species. It has numerous flower heads which can produce up to 50 flowering heads with 20 flowers a head and one seed per flower, resulting in 1,000 seeds a plant.
Buck's Horn Plantain
Buck’s Horn Plantain is a low growing perennial with a high salt tolerance which allows it to grow very close to the sea. Its leaves resemble stag deer’s antlers hence its name. It flowers mainly during spring and summer but can flower throughout the year. It reproduces by seed.
Drought and salt tolerant, galenia grows over and smothers existing vegetation by forming a thick dense mat. It invades coastal dunes, pastures, disturbed areas, lawns, roadsides and rocky outcrop vegetation. Galenia is known to produce nitrates that can be toxic to stock.
Common Ice Plant
The Common Ice Plant is native to Africa, Sinai and Europe and has fleshy leaves with distinctive bladder cells on the surface that look like dew or ice, their main function being to reserve water. It accumulates salt which can leech into the sand after the weed dies. Its leaves and seeds are edible, and crushed leaves can be used as a soap substitute. As a ground cover plant, it has the ability to smother natives.
European Tree Mallow
Originating in Europe, Marshmallow is a semi upright weed that becomes more erect as it matures. It is characterised by rounded, wrinkled leaves. It produces pale pink or white flowers growing in small clusters in leaf forks or on the stalks.
False Sow Thistle
The False Sow Thistle, native to the Mediterranean, is widespread throughout the dunes but does not grow in dense patches although it does compete with native plants. It has a yellow daisy with a red-brown centre and should not be confused with the native Dune Thistle (Actites magalocarpus). We have been cutting the flower heads off to see if we can hinder it spreading next year.
A native of Europe and Central Asia, it is also known as Lamb’s-tongue. It is a common weed with good drought tolerance, however it is not tolerant of salinity although we have had it growing amongst the dunes. Ribwort has been used for medicinal purposes in some parts of the world and it is being developed as a fodder crop in temperate Australia.
The African Daisy is native to South Africa and is regarded as an emerging environmental weed in South Australia. It starts blooming in spring and within Taperoo Dunes its flowers are white, but they come in a variety of colours elsewhere. Once established these invasive plants are drought tolerant and very tough, tolerating dry soils.
Indigenous to South Africa, it is often called by the common name soursob due to its sour flavour which is caused by the exceptionally high content of oxalic acid. The weed propagates largely through its complex underground bulb system and therefore difficult to eradicate, as pulling up the stems leaves the bulbs behind. Soil in which the plant has grown is generally contaminated with many small bulbs, therefore making it capable of spreading rapidly.
Native to south-eastern Australia, it can grow up to 6m in height and has small leathery leaves. It has white flowers occurring mostly during late winter and spring. It reproduces by seeds which are commonly dispersed by wind. Regarded as an environmental weed in South Australia.