Acacia dealbata, commonly known as silver wattle, blue wattle or mimosa,[2] is a species of flowering plant in the legume family, Fabaceae and is endemic to south-eastern mainland Australia. It is a bushy shrub or spreading tree with smooth bark, bluish grey or silvery and glaucousbipinnate leaves, spherical heads of yellow to bright yellow flowers, and straight to slightly curved pods. The Wiradjuri people of New South Wales use the name giigandul for the species.[3]
Acacia dealbata is an erect, bushy shrub or spreading tree that typically grows to a height up to 30m (98ft) and has smooth grey, brown or dark brown bark, deeply corrugated when old. The leaves are bipinnate, on a petiole up to 15mm (0.59in) long, with 6 to 30 pairs of pinnae, each with 10 to 68 pairs of narrowly oblong to linear pinnules0.7–5mm (0.028–0.197in) long and 0.4–0.8mm (0.016–0.031in) wide. The leaves are bluish grey or silvery and glaucous. The flowers are borne in spherical heads in racemes or in panicle-like groups on a hairy peduncle2–10mm (0.079–0.394in) long, each head with 13 to 42 yellow to bright yellow flowers. Flowering occurs from July to November, and the pods are straight to slightly curved, more or less flat and often slightly constricted between some or all of the seeds, slightly leathery, blue or purplish, with a white, powdery bloom.[4][5][6][7]
Taxonomy
Acacia dealbata was first formally described in 1822 by Johann Heinrich Friedrich Link in his Enumeratio Plantarum Horti Botanici Regii Berolinensis Altera.[8][9]
Along with other bipinnate wattles, A. dealbata is classified in the section Botrycephalae within the subgenus Phyllodineae in the genus Acacia. An analysis of genomic and chloroplast DNA along with morphological characters found that the section is polyphyletic, though the close relationships of many species were unable to be resolved. Acacia dealbata appears to be most closely related to A. mearnsii, A. nanodealbata and A. baileyana.[10]
Acacia dealbataLink subsp. dealbata[15] is a shrub or spreading tree up to 30m (98ft) with leaves mostly 50–140mm (2.0–5.5in) long, the heads with 22 to 42 pale yellow to yellow, sometimes bright yellow flowers.[7][14][16][17][18][19]
Acacia dealbata subsp. subalpinaTindale & Kodela[20] is a dense shrub or tree up to 3m (9.8ft), rarely to 10m (33ft), with leaves mostly 15–85mm (0.59–3.35in) long, the heads with 13 to 34 bright yellow flowers.[7][14][21][22][23][24]
The species has been widely introduced in Mediterranean, warm temperate, and highland tropical landscapes.[26]
As an invasive species
In the Western Cape of South Africa, the species is a Category 1 weed, requiring eradication; elsewhere in South Africa it is a Category 2 weed, requiring control outside of plantation areas.[27] In New Zealand, the Department of Conservation classes it as an environmental weed.[28] In Portugal, the species makes part of the official list of invasive species (along with other acacias).[29] In California, the species is invasive and appears to displace many native species, also threatening the habitat of the endangered Mount Hermon June beetle.[30][31]
Use in horticulture
'Kambah Karpet', a cultivar discovered at the Kambah Village
Acacia dealbata is widely cultivated as an ornamental plant in warm temperate regions of the world,[11] and is naturalised in some areas, including Sochi (Black Sea coast of Russia), southwestern Western Australia, southeastern South Australia, Norfolk Island, the Mediterranean region from Portugal to Greece and Morocco to Israel, Yalta (Crimea, Ukraine), California, Madagascar,[32] southern Africa (South Africa, Zimbabwe), the highlands of southern India,[26] south-western China and Chile.[33][34][35][36] It is hardy down to −5°C (23°F),[37] but does not survive prolonged frost.[11] It prefers a sheltered position in full sun, with acid or neutral soil. It has gained the Royal Horticultural Society's Award of Garden Merit.[37][38]
Uses
'Mimosa' blossoming in an urban setting in Italy
The flowers and tip shoots are harvested for use as cut flowers, when it is known by the florist trade as "mimosa" (not to be confused with the genus of plants called Mimosa). In Italy,[39] Albania, Russia and Georgia the flowers are also frequently given to women on International Women's Day.[citation needed] The essence of the flowers, called 'mimosa', or in older texts, 'cassie', is used in perfumes.[40] The leaves are sometimes used in Indian chutney.[11]
In Australia, the Ngunnawal people of the ACT and Wiradjuri people of NSW used the bark to make coarse rope and string, the resinous sap for glue or to mix with ash to make poultices, the timber for tools, and the seeds to make flour.[41][3] The timber is useful for furniture and indoor work, but has limited uses, mainly in craft furniture and turning. It has a honey colour, often with distinctive figures like birdseye and tiger stripes. It has a medium density (540–720kg/m3), and is similar to its close relative blackwood, but of lighter tone without the dark heartwood.[citation needed]
In culture
Acacia dealbata is one of the most readily-available for use in Wattle Day celebrations or commercial bouquets. It is also one of a few Australian plant species symbolically commemorated in Japan, allegedly being the first plant to bloom in the aftermath of the Hiroshima atomic bomb in August 1945.[42]
↑ "Acacia dealbata". Royal Horticultural Society. Retrieved 11 December 2022.
1 2 Williams, Alice; Sides, Tim, eds. (2008). Wiradjuri Plant Use in the Murrumbidgee Catchment. Murrumbidgee Catchment Management Authority. p.19. ISBN978-0-7347-5856-9.
1 2 Kodela, Phillip G.; Tindale, Mary D. Kodela, Phillip G. (ed.). "Acacia dealbata". Flora of Australia. Australian Biological Resources Study, Department of Climate Change, Energy, the Environment and Water: Canberra. Retrieved 27 August 2025.
1 2 Kodela, Phillip G.; Harden, Gwen J. "Acacia dealbata". Royal Botanic Garden, Sydney. Retrieved 27 August 2025.
1 2 Entwisle, Timothy J.; Maslin, Bruce R.; Cowan, Richard S.; Court, Arthur B. "Acacia dealbata". Royal Botanic Gardens Victoria. Retrieved 27 August 2025.
↑ Brown, Gillian K.; Ariati, Siti R.; Murphy, Daniel J.; Miller, Joseph T. H.; Ladiges, Pauline Y. (1991). "Bipinnate acacias (Acacia subg. Phyllodineae sect. Botrycephalae) of eastern Australia are polyphyletic based on DNA sequence data". Australian Systematic Botany. 19 (4): 315–26. doi:10.1071/SB05039.
↑ George, Alex S.; Sharr, Francis A. (2023). Western Australian Plant Names and Their Meanings - A Glossary (fifthed.). Kardinya: Four Gables Press. p.181. ISBN9780645629538.
↑ Harrison, Lorraine (2012). RHS Latin for Gardeners. United Kingdom: Mitchell Beazley. ISBN978-1845337315.
↑ Kodela, Phillip G.; Tindale, Mary D. Kodela, Phillip G. (ed.). "Acacia dealbata subsp. dealbata". Flora of Australia. Australian Biological Resources Study, Department of Climate Change, Energy, the Environment and Water: Canberra. Retrieved 27 August 2025.
1 2 Kodela, Phillip G.; Tindale, Mary D. Kodela, Phillip G. (ed.). "Acacia dealbata subsp. subalpina". Flora of Australia. Australian Biological Resources Study, Department of Climate Change, Energy, the Environment and Water: Canberra. Retrieved 27 August 2025.
1 2 Kull, Christian A.; Shackleton, Charlie M.; Cunningham, Peter J.; Ducatillon, Catherine; Dufour-Dror, Jean-Marc; Esler, Karen J.; Friday, James B.; Gouveia, António C.; Griffin, A. R.; Marchante, Elizabete; Midgley, Stephen J.; Pauchard, Aníbal; Rangan, Haripriya; Richardson, David M.; Rinaudo, Tony; Tassin, Jacques; Urgenson, Lauren S.; von Maltitz, Graham P.; Zenni, Rafael D.; Zylstra, Matthew J. (2011). "Adoption, use and perception of Australian acacias around the world". Diversity and Distributions. 17 (5): 822–836. Bibcode:2011DivDi..17..822K. doi:10.1111/j.1472-4642.2011.00783.x. hdl:10533/134844.
↑ "Archived copy"(PDF). Archived from the original(PDF) on 2013-06-27. Retrieved 2013-05-02.{{cite web}}: CS1 maint: archived copy as title (link)Kull, Christian A.; Rangan, Haripriya (2008). "Acacia exchanges: Wattles, thorn trees, and the study of plant movements". Geoforum. 39 (3): 1258–1272. doi:10.1016/j.geoforum.2007.09.009.
1 2 "Acacia dealbata". www.rhs.org. Royal Horticultural Society. Retrieved 14 February 2020.
↑ "AGM Plants - Ornamental"(PDF). www.rhs.org. Royal Horticultural Society. July 2017. p.1. Retrieved 14 February 2020.
↑ "National Wattle Day 2012". Friends of the Australian National Botanic Gardens. 6 September 2012. Retrieved 22 August 2024. Representatives of the Embassy of Japan attended in recognition of the silver wattle (Acacia dealbata) being the first plant to bloom after the devastation of Hiroshima by the atomic bomb in August 1945.
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