Acacia stricta

Acacia stricta (Andrews) Willd.

Family: Fabaceae Common name: hop wattle; straight wattle Category: proposed 1a (NEMBA) Description Erect shrub or small tree, 1–8 m high. Branches angled or flattened. Leaves narrow, elliptic, up to 12cm long, prominent midvein and net-venation. Flowers yellow balls held close to the stems, occurring in groups of 2-4 in the axils of the leaves, appearing in spring. Pods straight up to 100 mm long and 5 mm wide. Seeds coat hard, the seed stalk expanded at one end but does not encircle the seed. Hop wattle might be mistaken for rooikrans (Acacia cyclops) or long-leaved wattle (Acacia longifolia). The differences between these species are tabulated below.

Acacia stricta leaves	Acacia stricta flowers

Distribution Hop wattle is native to Australia (Victoria, New South Wales, Tasmania). How it spreads Seeds with sporadic strong winds and also appears to be easily dispersed via human activties and soil movement (most likely road construction). However, the majority of the seeds accumulate under the tree canopy.

History in South Africa Hop wattle was probably introduced in South Africa as an ornamental plant and for soil stabilization and has recently been recorded in the Knysna area (Western Cape), mostly on plantation land owned by MTO forestry. Environmental and economic impact Hop wattle is a fast growing and drought tolerant species, which can withstand both low and high temperatures. It forms persistent seed banks, and seedlings may continue to emerge for many years after the plant has been removed. The species is also considered a high risk species in terms of invasiveness. It invades roadsides, watercourses and gaps in plantations. How to eradicate Hop wattle is currently controlled by uprooting or cut-stump treatment using a glyphosate herbicide. There is no herbicide or biological control agent registered for this species in South Africa. What can you do to help? Report sightings of these plants to the Early Detection and Rapid Response Programme (EDRR) at SANBI. We will need to know its locality (the exact locality, supply any landmarks of GPS information if possible). Contact details Kanyisa Jama Email address: alienplants@sanbi.org.za Tel: 021 799 8762 References

• South African Plant Invaders Atlas. 2010. SAPIA News no. 8. ARC-Plant Protection Research Institute. Available on line at: http://www.dargieconservancy.org.za/documents/sapia08.pdf
• Broughton, V.H.1986. Phyllode structure, taxonomy and distribution in some Australian acacias. Australian Journal of Botany 34: 663-674. Available on line at: http://plantnet.rbgsyd.nsw.gov.au/PlantNet/WattleWeb/refs.php
• South African plants invaders atlas database. ARC- Plant protection research institute, Pretoria, South Africa. Available on line at: http://www.agis.agric/wip
• Pheloung P. C., P. A. Williams and S. R. Halloy. 1999. A weed risk assessment model for use as a biosecurity tool evaluating plant introductions. Journal of Environmental Management 57: 239–251.

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Compiled Buhle Mthembu and Thulisile JacaAugust 2011