Description
Asparagus Fern (Asparagus aethiopicus) is a perennial herb with many erect persistent stems about 1 m long. It reproduces both by seed and vegetatively from rhizomes (underground stems) and tubers. The roots are either well developed and fleshy, bearing numerous fleshy white tubers roughly ovoid in shape and 1.5 to 3 cm long, or finer and fibrous. The root system forms dense underground clumps and mats.
Stems are hairless, green to brown, often irregularly twisted, with older stems bearing short straight stiff pungent spines, 5-10 mm long, just below many of the numerous short leafy side branches. The “leaves”, which occur in clusters of 1-5, are really cladodes (short, flattened stems that look and function like leaves). They are 1.5 to 2.5 cm long, 0.2 to 0.3 cm wide and taper to a fine short point. The true leaves are small scales that occur at the base of the cluster of cladodes.
The white-pink flowers, each about 5 mm in diameter, are borne spaced out along a short stem. The fruit is a berry, 5-8 mm wide, green at first then maturing to a glossy red. It contains one or a few black, globular seeds 3-5 mm diameter.
For further information and assistance with identification of Asparagus Fern contact the herbarium in your state or territory.
Distribution:
Asparagus Fern has naturalised in south-eastern Queensland and along the coast of New South Wales. In Queensland Asparagus Fern has naturalized in coastal areas and on off-shore islands south from about Hervey Bay to the Gold Coast but is also found much further north in the Mackay area. In New South Wales it is common along the coast from the Queensland border to near Batemans Bay. The weed is also a serious problem on Lord Howe Island and Norfolk Island.
There have been a few recent collections from Victoria in the suburban coastal Black Rock to Mornington area on Port Phillip Bay. In Western Australia there a several collections from coastal areas near suburban Mullaloo, just north of Perth, and further south near the towns of Augusta and Albany.
The species may also be naturalized in South Australia.
Habit:
Herb
Key points:
- Asparagus Fern (Asparagus aethiopicus) is a perennial herbaceous species that has become a serious environmental weed.
- It is a common garden plant which easily re-establishes after being dumped as garden waste.
- Seeds are spread by birds which feed on the fruit both in gardens and at sites of weed infestation.
- The extensive root system and prolific seed production makes control difficult requiring very long-term commitment over decades, with repeated control action and monitoring.
How it spreads:
Vegetative dispersal of Asparagus Fern is by sale of nursery stock to gardeners, and by the dumping of garden refuse containing tubers and seed. Birds feed on the coloured fruit both in gardens and in the wild and disperse the apparently indigestible seed in scats.
Where it grows:
Asparagus Fern is confined to warm temperate regions with rainfall of 500 to 1500 mm per year. It usually prefers infertile, shallow, sandy soils. Asparagus Fern likes shady niches and has been recorded as occurring in woodlands, littoral rainforest, rainforest gullies, on rocky headlands, in a variety of coastal dune communities, immediately adjacent to mangrove communities, on riverbanks, on sandstone sites with sandy soil, in moist weedy gullies and on shady roadsides. It is also naturalized in cemeteries.
Flower colour:
White
Impacts:
Asparagus Fern forms dense blankets of growth above ground and a profusion of rhizomes and tubers below ground which suppresses other ground flora and reduces available soil moisture and nutrients. It is able to tolerate dry periods due to its well developed rhizomes and numerous tubers.
Origin:
Asparagus Fern is native to South Africa where it is restricted to the Cape Province and Natal.
History:
Asparagus Fern was introduced to Australia in the late 19th century as a garden or pot plant and has since become naturalized.
