Golden-wreath Wattle

Acacia saligna (Labill.) H.L.Wendl.

Synonyms - Acacia cyanophylla, Mimosa saligna, Racosperma salignum

Family: - Mimosaceae

Names:

Acacia was the name of a thorny Egyptian tree.

Saligna refers to the Willow (Salix spp.) like habit of the plant.

Wattle comes from British settlers making wattle and daub buildings using Callicoma serratifolia branches which was then called Black Wattle and is similar to the other Acacias of the area.

Golden Wreath Wattle refers to the sprays of golden flowers and its membership of the Wattle or Acacia genus.

Other Names:

Blue-leafed Wattle

Kudjong

Orange Wattle

Western Australian Golden Wattle

Summary:

Golden Wreath Wattle (Acacia saligna) is an often weeping, bushy shrub or small tree, 2-6 m tall with grey, smooth bark and pendulous 'leaves' that are 70-250 mm long by 4-20 mm wide. It has 3-30 mm long sprays of globular golden flower heads that are 7-10 mm in diameter and have 25-55 tiny flowers from July to November. The pods are flat, straight, 80-120 mm long by 4-6 mm wide and are slightly constricted between the elliptical seeds which are shiny dark brown to black and 5-6 mm long. It has been widely planted in salt land reclamation sites.

Description:

Cotyledons:

Two.

First leaves:

Pinnate.

Leaves:

Alternate usually but may be in clusters. On mature plants there are no true leaves and only dark green, leaf like phyllodes which are flattened petioles.

Phyllodes: Bluish green or green phyllodes variable texture from thin and flexible to thick and fleshy to leathery and straight or curved, narrowly elliptic, often pendulous, 70-250(300) mm long by (2)4-20(50) mm wide and larger toward the base of the plant. Mid vein is prominent and branched laterals are conspicuous. Resinous. 1 small, disk shaped, conspicuous gland, 1-2 mm diameter and 0-3 mm from the base of the phyllode. Tip pointed with a finer tip (mucro) and no callus. Sides curved to straight. Base tapering. Hairless.

Stipules - Fall off before the leaf matures.

Petiole - Flattened and looks like a leaf. Base of petiole swollen to form the wrinkled pulvinus, 1-2 mm long.

Blade - None on mature trees, bipinnate on juvenile foliage.

Stems:

Erect, spreading, 2-6(10) m tall. Sometimes multi-stemmed.

Branchlets almost circular in cross section (may be angled or flattened initially) and often drooping and slightly curved. Branchlets are initially yellow green to red green and become grey and roughened with age. They may be hairy when young but become hairless with age.

Bark - Dark brownish grey, smooth or finely fissured.

Coppices when damaged.

Flower head:

Globular heads, 7-10 mm diameter with 22-55(75) flowers and enclosed by overlapping bracts when young. 2-12 heads on 4-15(20) mm long, usually hairless stalks (peduncles) in an extended axillary inflorescence with an axis (rachis) that is 3-30(50) mm long, hairless and sometimes zig-zag.

Flowers subtended by a small bracteole.

Flowers:

Orange to yellow. Bisexual. Actinomorphic.

Ovary - Superior. Hairless. One carpel. Numerous ovules

Style - Threadlike

Calyx - Shortly 5 acutely lobed. Sepals united for 80% of their length. Hairless

Petals - 5. Hairless.

Stamens - Numerous and free.

Anthers - Fertile. 2 celled. Opening by longitudinal slits

Fruit:

The pod is light brown, linear, thinly leathery and sometimes has a whitish bloom. It is straight to curved, flat but somewhat constricted between the seeds, (50)80-120(140) mm long by 4-6 mm wide, hairless or occasionally slightly hairy. The edges are paler and thickened. The 4-10 seeds are arranged longitudinally. Pod matures in late spring to summer. Opens by two valves that remain straight.

Seeds:

Shiny, dark brown to black, ellipsoid and 5-6 mm long by 3-3.5 mm wide.

The seed stalk (funicle) is pale, persistent and expanded near the seed (arilate).

Roots:

Taproot with woody branching laterals. Forms suckers.

Key Characters:

Branchlets glabrous.

Phyllodes tapered into a wrinkled pulvinus 1-2 mm long.

Phyllodes usually >6 mm wide with a marginal gland adjacent to the pulvinus.

Phyllodes acute to sub acute, with a straight or oblique mucro but not pungent.

Phyllodes with a distinct mid vein, conspicuous laterals and hairless.

Axillary racemes with 2-10 flower globose heads on slender peduncles

Flowers yellow and actinomorphic.

Ovary superior.

Stamens all free, more than 10 and usually < 0.5 mm long, orange yellow

Pods 4-6 mm wide, only slightly constricted between the seeds

Adapted from J.R. Wheeler, G. Harden.

Biology:

Life cycle:

Perennial. Seed tends to germinate in the rain following fire or disturbance. The young seedlings grow quickly, developing a strong root system. Juvenile plants mature and set seed 2-3 years after germination. Mature plants set large amounts of seed much of which may remain dormant for many years in the soil. The plant lives for 10-20 years.

Physiology:

Salt, salt spray, drought and frost tolerant. It is also shade tolerant but prefers full sun situations.

Fast growing.

Roots can fix atmospheric nitrogen.

Reproduction:

Sets seed within 2-3 years of germination. Self sows, suckers and coppices readily.

Flowering times:

July to November in WA. Mainly August to September in Perth.

July to September in NSW.

Spring in SE Australia.

Seed Biology and Germination:

Has dormant seed.

Up to 3500 seeds per square metre have been measured under established stands.

Seed can remain viable in the soil for more than 10 years. High humidity reduces seed longevity in the field.

Vegetative Propagules:

Suckers from the roots especially after fire or disturbance.

Hybrids:

Allelopathy:

Population Dynamics and Dispersal:

Long distance spread is usually by intentional plantings. Medium distance spread is mainly by earth moving equipment and dumping of garden refuse. Local spread by ants, birds and slashing. It also produces suckers and will coppice when damaged.

There is often a mass germination of seed after fire or disturbance.

It is available commercially from nurseries.

Origin and History:

WA native plant. Probably native to the Murchison and naturalised in more southern areas

Widely planted for salt land reclamation and often planted on roadsides and in gardens.

In eastern Australia it was often used for dune rehabilitation after sand mining.

Distribution:

ACT, NSW, NT, QLD, SA, TAS, VIC, WA.

Widespread in southern WA. Occurs in the Murchison, Coolgardie, Geraldton Sandplains, Swan Coastal Plain, Jarrah Forest, Warren, Avon Wheatbelt, Mallee and Esperance Plains regions.

Naturalised in NSW, Queensland, SA, Victoria, Tasmania, South Africa and USA.


Courtesy Australia's Virtual Herbarium.

Habitats:

Tolerates a wide range of habitats.

Coastal shrublands and woodlands, heathlands, moist forests and riparian areas.

Climate:

Cool temperate. Mediterranean.

Soil:

Tolerates a wide range of soils from sands to clays, including semi saline areas.

Plant Associations:

Significance:

Beneficial:

Used in salt land reclamation and dune stabilisation.

Used as a low quality fodder.

Ornamental, gums, shelter, fibre, fuel wood.

Commercially planted in North Africa and the Middle East for windbreaks, coastal sand dune stabilization, fuel wood and fodder production

Detrimental:

A major weed of South Africa.

Naturalised in NSW, Queensland, SA, Victoria, Tasmania, South Africa and USA.

Environmental weed.

Classified as a “Garden Thug”.

Toxicity:

Not recorded as toxic and used as a fodder.

Symptoms:

Treatment:

Legislation:

None.

Management and Control:

Picloram, Garlon and glyphosate are used for chemical control as overall sprays, stem injection or cut stump.

Use Garlon 480 at 1:400 and Roundup CT at 1:200 as an overall spray for control of juvenile trees and 2 L/ha Garlon 480 for control of seedlings.

2 L/ha of Roundup (360 g/L) controls seedlings in autumn winter and spring but 4 L/ha was required for late summer applications.

Fire destroys the mature trees but usually leads to a mass germination of seedlings. However if these seedlings are controlled it very quickly reduces the seed bank in the soil. Seedlings tend not establish in mature stands.

A long term control plan is usually required for success.

Target areas that have been recently burnt because these will be more prone to invasion and the seed bank will be reduced due to the fire induced germination of seed.

Thresholds:

Eradication strategies:

In large dense stands a hot fire may be used to improve access and encourage seed to germinate so that it may controlled by herbicides and reduce the soil seed bank.

For mature or juvenile trees, inject the stems with 1 mL Tordon Timber Control herbicide per 1.5 metres of height in autumn or spring when trees are actively growing.

For seedlings, apply 4 L/ha of glyphosate (450 g/L) or spray until just wet with a mixture of 100 mL of glyphosate (450 g/L) per 10 L of water.

For juvenile trees, spray a mixture of 100 mL of glyphosate (450 g/L) plus 25 mL Pulse Penetrant per 10 L of water onto the foliage until just wet. A concentrated mix of 1 part glyphosate with 2 parts water can also be applied using a window washer bottle. Apply about 3 mL of this solution per square metre of foliage. Lontrel®750 at 2 kg/ha may provide more selective control in some situations.

A basal bark treatment is often the most cost effective. Apply a mixture of 1 L of Access® in 60 L of diesel to the lower 50 cm of the trunk and repeat in 6 months if necessary.

Repeat treatments every second year to ensure that no trees reach an age where they can set seed.

This species suckers profusely which makes mechanical control difficult without the aid of herbicides. Use glyphosate, Garlon®, Grazon® Access® or Tordon® Timber Control to paint the stumps immediately after felling or inject herbicide into the trunk.

A large number of seedlings often emerge in the season after felling, burning or spraying. If these are left the infestation may become worse. Follow up every 2-3 years to ensure no trees reach an age where they set seed.

If glyphosate is not providing good control then try Garlon®, Grazon®, Hotshot®, Starane® or clopyralid(300g/L). Test various times of treatment in your area. Avoid further burning or denuding of the area as this will encourage seedling establishment.

Eradication may take many years due to the dormant seed bank. Smoked water, fire and increased humidity may be useful in reducing seed dormancy.

In agricultural situations, plant perennial pastures to reduce seedling establishment.

Don't buy or plant them in gardens outside of their native range which is in WA.

Herbicide resistance:

None reported.

Biological Control:

Unlikely because many are Australian native species.

Related plants:

See A key for weedy Acacias and similar native species

There are more than 500 native Acacia species in WA.

Weedy and look-alike species include

Acacia Hedge (Acacia paradoxa). Noxious weed.

Black Wattle (Acacia decurrens) Bark used for tanning.

Blackwood (Acacia melanoxylon) Bark used in tanning.

Blakely's Wattle (Acacia blakelyi) Used in revegetation.

Brigalow (Acacia harpophylla)

Burrow's Wattle (Acacia burrowii)

Caterpillar Wattle (Acacia lasiocalyx) Used in revegetation.

Cedar Wattle (Acacia elata) Ornamental

Chisholm's Wattle (Acacia chisholmii)

Coast Myall (Acacia binervia) is toxic to stock.

Cootamundra Wattle (Acacia baileyana) Ornamental

Curracabah (Acacia concurrens)
Currawong (Acacia sparsiflora)
Cutch Tree (Acacia cutechu) Noxious weed.

Deane's Wattle (Acacia deanei)

Dwarf Silver Wattle (Acacia nano-dealbata)

Flinders Ranges Wattle (Acacia iteaphylla)

Gidgee (Acacia cambagei)

Georgina Gidgee (Acacia georginae) is toxic to stock.

Golden Wattle (Acacia pycnantha)

Golden-wreath Wattle (Acacia saligna) Used in revegetation.

Gosford Wattle (Acacia prominens) Ornamental

Green Wattle (Acacia mearnsii) Bark used in tanning.

Hop Mulga (Acacia craspedocarpa)

Manna Wattle (Acacia microbotrya) Used in revegetation.

Mimosa bush (Acacia farnesiana)

Motherumbah (Acacia cheelii)

Mountain Cedar Wattle (Acacia elata)

Mulga (Acacia aneura) Used for fodder.

Prickly Acacia (Acacia nilotica). Noxious weed.

Prickly Moses (Acacia pulchella)

Queensland Silver Wattle (Acacia podalyriifolia)

Red Wattle (Acacia sylvestris)

Silver Wattle (Acacia dealbata)

Snowy River Wattle (Acacia boormanii) Ornamental

Sweet Wattle (Acacia suaveolens)

Sydney Golden Wattle (Acacia longifolia)

White Sally (Acacia floribunda)

Acacia glaucescens is toxic to stock.

Acacia jucunda

Racosperma species.

Plants of similar appearance:

Golden Wattle (Acacia pycnantha) is somewhat similar but usually larger and has a longer inflorescence, a stouter raceme axis and peduncles, no basal raceme bracts, conspicuously attenuate phyllode bases with longer pulvini and smaller glands.

Acacia microbotrya has different seeds and pods.

Acacia rostellifera has different seeds and pods.

References:

Bodkin, F. (1986). Encyclopaedia Botanica. (Angus and Robertson, Australia).

Blood, K. (2001). Environmental weeds: a field guide for SE Australia. (CH Jerram & Associates, Australia). P84. Photo.

Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney).

Harden, Gwen J. (1991). Flora of NSW. (Royal Botanic Gardens, Sydney). Volume 2. P375. Diagram.

Hussey, B.M.J., Keighery, G.J., Cousens, R.D., Dodd, J. and Lloyd, S.G. (2007). Western Weeds. A guide to the weeds of Western Australia. (Second Edition). Plant Protection Society of Western Australia, Perth, Western Australia. P194.

Lazarides, M. and Cowley, K. and Hohnen, P. (1997). CSIRO handbook of Australian Weeds. (CSIRO, Melbourne). #3.25.

Marchant, N.G., Wheeler, J.R., Rye, B.L., Bennett, E.M., Lander, N.S. and Macfarlane, T.D. (1987). Flora of the Perth Region. (Western Australian Herbarium, Department of Agriculture, Western Australia). P229.

Maslin, B.R. (2001) Wattle. Acacias of Australia. CD.

Muyt, A. (2001). Bush Invaders of South-East Australia: a guide to the identification and control of environmental weeds found in South East Australia. (R.G and F.J. Richardson, Australia). P159. Photo.

Paczkowska, G. and Chapman, A. (2000). The Western Australia flora: a descriptive catalogue. (Wildflower Society of Western Australia (Inc), the Western Australian Herbarium, CALM and the Botanic Gardens & Parks Authority). P322.

Tame, T.(1992). Acacias of Southeast Australia. Kangaroo Press, Kenthurst, NSW, Australia. P128. Diagram.

Wheeler, Judy, Marchant, Neville and Lewington, Margaret. (2002). Flora of the South West: Bunbury - Augusta - Denmark. (Western Australian Herbarium, Bentley, Western Australia). P676.

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.