Asparagus aethiopicus L. cv. Sprengeri
(Asparagaceae – the asparagus family)
common names: Ground Asparagus Fern, Asparagus Fern, Sprenger’s Asparagus
Ασφαραγος (aspharagos) was the ancient Greek name for the plant Asparagus officinalis, the asparagus we eat; æthiopicus is Latin for ‘Ethiopian’. Sprengeri is for Carl Ludwig Sprenger (1846–1917), who collected the plant in Natal Province, South Africa, for his employer, Dammann & Co, an Italian seed company. The plant became very popular in Europe as an ornamental plant. It was originally described by the German botanist Carl Sigismund Kunth.
This pretty fern† and two of its close relatives, Asparagus africanus and Asparagus plumosus, all naturalized in Australia, are highly invasive weeds of bushland, and are declared plants Class 3 in Queensland, which means that their supply or sale is prohibited. They are Class 4 in parts of NSW, particularly in the North Sydney region, Parramatta and the Blue Mountains. With their underground rhizomes, they are some of the most difficult and labour-intensive weeds to remove from natural bushland. They out-compete and smother natural vegetation, their rhizomes and fibrous, tuberous roots forming dense mats just below the soil surface, interfering with the establishment and survival of native plants. Their seeds are spread by birds and water. The rhizomes and fruits are also easily spread in dumped garden waste, any small fragment of rhizome being enough for regrowth. The water tubers, however, contain no food, and the plant cannot regenerate from them.
Ground asparagus fern is a perennial groundcover plant with sprawling wiry stems to 2 m long. The ‘leaves’ are cladodes, flattened, alternate, to 2.5 cm long. Small spines may be present in the leaf axils. The tiny (3–4 mm long) flowers are numerous in racemes, both sepals and petals white. Berries are produced, 5–8 mm in diameter, green, ripening to red, containing 1 to a few black seeds about 4 mm in diameter.
Asparagus africanus is the climbing variety of the genus. It easily scrambles over other vegetation up to 12 m into the canopy, and can be a serious pest, especially in rainforest.
Asparagus plumosus, the feathered asparagus fern, has its stems covered with sharp spines. It is a slender, wiry, perennial climbing scrambler growing to 5 m or more in height on supporting vegetation. Its trailing stems may be several metres long, and are often branched and tangled. The leaves are reduced to spine-like scales to 5 mm long, that are not hardened. Flowering occurs from spring to autumn with small greenish white flowers borne in small clusters or singularly at the ends of the branches. The fruits are small fleshy berries containing 1–3 seeds. They are green when developing, maturing to purple-black. This species prefers rainforest or brigalow communities, wet eucalypt communities, and disturbed areas such as roadsides and cleared land.
† it isn't actually a fern, of course
Photographs © Donald Simpson, taken in Picnic Bay 2010