Skeleton weed (Chondrilla juncea) is a perennial forb and is considered a noxious weed. It can grow in disturbed soils of roadsides, croplands, especially irrigated grain fields, waste places and residential properties. It is a thin, spindly plant which reaches a meter in height. It starts from a basal rosette of leaves and branches extensively, often forming a weedy thicket.
Pinus elliottii (Pinaceae)
Coniferous tree 15-30m high with dark green, open crown of modest spread, free of branches to a considerable height. Dark green leaf needles in bundles of two or three, coarse and stiff and crowded at ends of branchlets. This tree produces yellowish to pale brown cones 6-14cm long
Small round-leaved prickly pear
The small round-leaved prickly pear is a succulent branched shrub that grows up to 1.5m tall. The leaf-like pads are grey-green and egg-shaped, with the narrower end at the base, reaching 15-30cm long and 12-20cm wide. The yellow to white spines, mainly found in the top half of the cladode, are 1-6cm long, slightly curved and very hard. The flowers are yellow, occasionally reddish, funnel-shaped and 5-8cm in diameter and the same in length. The plant bears purple, fleshy, edible fruits.
Small salvinia is a rapidly growing, aquatic floating fern that is used in planted aquaria and ponds. Originating in South America, this beautiful yet invasive plant has extended its influential range into South Africa. It is well established at Hartbeespoort Dam and forms dense mats within marginal vegetation. Light drives the reproduction and growth of this plant.
Smelter's bush is a semi-herbaceous annual up to 1m high, bearing yellow flowers in summer.
Smooth cordgrass is adapted to living in salt marshes and estuaries and was found growing in the Great Brak estuary between Mossel Bay and George in 2004. Research shows that, if left unmanaged, the population in the Great Brak estuary could spread at a rate 0.162 hectares per year, possibly eventually covering 41% of the total vlei area. Currently, the plant occupies less than one hectare of the intertidal marsh.
Peniocereus serpentinus (= Nyctocereus serpentinus)
Erect stems 2-3 metres tall with 10-12 slightly rounded ribs. Spines are soft, long and interlacing and white or brown in colour. Flowers open at night and are white inside and tinged with red on the outside. Floral tubes are up to 25 cm long. The fruit turns red and has a reddish pulp inside with large black seeds.
In its native range it grows along sandbanks of wetlands and river terraces, as well as lake shores. It is eaten by waterfowl such as geese and ducks. It is a popular ornamental plant, but is highly invasive and aggressive.
A reed-like shrub up to 2,5m high with long, slender, cylindrical green branches and almost leafless. Leaves are blue-green, silky beneath, and deciduous. Fragrant yellow flowers are borne in terminal clusters 30-40cm long from August to November. Fruits are flattened brown pods to 75mm long initially covered with white silky hairs. This plant is poisonous.
Cirsium vulgare (Asteraceae)
Spiny, herbaceous biennial which forms a large, flat rosette of leaves and a deep tap root in the first year and numerous branched stems up to 1,5m high in the second year. Stems have spiny wings. Dark green leaves with stiff hairs above and white woolly beneath. Pink to mauve thistle-like flowers surrounded by spiny bracts appear from September to April. This plant invades grassland, roadsides, vlei and dam margins and river banks in cool, high rainfall areas