Asparagus weeds - Weeds Australia

Asparagus africanusAsparagus africanus is most commonly known asclimbing asparagus, but is also known as asparagusfern or ornamental asparagus. It was previouslycalled Protasparagus africanus (Lam.) Oberm.Origin and distributionAsparagus africanus was introduced to Australiaas a garden ornamental from southern Africa andhas escaped from cultivation to become a majorweed of natural vegetation. The earliest naturalisedspecimens were collected from the Ipswich area,west of Brisbane in the 1940s. The distribution ofA. africanus extends from central west QLD andalong the coast from northern QLD to central NSW.It is particularly common in coastal districts nearsettlements.Climate modelling indicates that A. africanus couldexpand its range in coastal regions from far northQLD to southern VIC, as well as coastal areas of SAand south-west Western Australia (WA), althoughthere is low confidence in the current model andfurther work should be done (Scott and Batchelor2006).Habitat in AustraliaAsparagus africanus occurs in a range of habitats,but is primarily a weed of sub-tropical to tropicalforests, rainforest margins, littoral rainforests,hind dunes, open woodlands, riparian corridors,mangroves, brigalow scrub (Acacia harpophylla)and wet eucalypt forests. It also invades urbanbushland and roadsides and is commonly foundin ecotone areas (the transition area between twoplant communities), disturbed bushland, parks andgardens. It is moderately tolerant to drought stress.Environmental impactsAsparagus africanus grows quickly and producesdense thickets of foliage that can climb anddominate the canopy layer, smother native herbsand shrubs and form monocultures, which in turncan alter the functioning of the native ecosystem.#Asparagus africanusNRM BoundaryNo Reported OccurrenceCurrent distribution of Asparagus africanusInfestations are quick to expand, as the welldeveloped root system enables rapid growth,even under harsh conditions such as drought orimpoverished soils. The fibrous roots form densemats just below the soil surface that may interferewith the germination and seedling survival of nativeplants (Navie and Adkins 2008).In south-eastern QLD, A. africanus is ranked amongthe top ten most invasive plants, and extensiveinfestations of A. africanus threaten remnantbrigalow scrub (Batianoff and Butler 2002) whichis listed (Brigalow – Acacia harpophylla dominantand co-dominant) as an endangered ecologicalcommunity under the EPBC Act.Biology and ecologyAsparagus africanus is a long-lived climber orscrambling sub-shrub that can form woody stems.The stems grow in a twining fashion and developlarge, sharp spines. Stems originate from a basalcrown (up to 60 cm in diameter) consisting ofshort, fleshy rhizomes (see page 4 for root and stemstructure). Plants are perennial, retaining aboveground foliage year round. Unlike A. aethiopicus,the roots do not form distinct tubers but develop13