ABCDEFGHIJKLMNOPQRSTUVWXYZ

Natural populations

Melaleuca uncinata belongs to a species complex that comprises at least 11 species [1]. As currently recognised this species has two major disjunct occurrences: one in Western Australia where it occurs in the Coolgardie-Esperance region, and the other on the Eyre Peninsula in South Australia. The extent of its occurrence further east of the Eyre Peninsula is currently under review but it is suspected to extend as far east as western Victoria and the south west of New South Wales [1]. Melaleuca uncinata is a densely branching shrub to 4 m tall with peeling papery bark. It grows on a range of deep, light-textured soils mainly loams, sandy loams and sandy clay loams, often associated with mallee woodlands.

Flowering and seeds

This species flowers during spring [2]; ripe fruit are present during the summer months and may be held on the plant for at least a season. There are over 2200 viable seeds per gram; seeds start to germinate in about 14 days if grown at 20°C with no pretreatment required [2]. Without application of fertiliser seedlings of this species will not grow.

Cultivation and uses

Natural populations of this species and some of its close relatives, particularly M. atroviridis which is widespread throughout the Western Australian wheatbelt region, are used to produce broombush fencing. Plants are mainly harvested from natural stands but plantations have been established over the past decade [3,4]. This species has potential to be grown as a source of broombush fencing on saline and waterlogged soils in areas that receive as low as 200 mm mean annual rainfall [3,4,5].

Key descriptors:
Climate parameters
Annual rainfall: 200-700 mm
Rainfall distribution pattern: winter
Mean annual temperature: 12-22 °C
Mean max. temperature of the hottest month: 22-35 °C
Mean min. temperature of the coldest month: 3-9 °C
Frosts per year: up to 20
Frost intensity: light to moderate (0 to -5°C)
Altitude: 0-350 m
Tolerance of climate extremes
Drought: known to be moderately drought tolerant
Frost: tolerates frosts in the 0° to -5°C range
Soil factors
Texture: clay loam, duplex texture contrast soils, loam, sandy loam, sandy clay loam or sand
Soil pH reaction: neutral (6.5-7.5) or alkaline (greater than 7.5)
Soil depth: moderate to deep (30-100 cm or greater)
Drainage: well-drained
Salinity: slightly to moderately saline or non-saline
Tolerance of adverse soils
Extremes in pH: alkalinity
Extremes in texture: sand
Salinity: moderate (-8 dS m-1) or slight (2-4 dS m-1)
Soil waterlogging tolerance: nil - sensitive to waterlogged soils

Biological traits under cultivation
Habit: evergreen shrub less than 2 m tall, multi-stemmed from or near ground level or shrub or small tree less than 5 m tall
Longevity: moderate to long lived (>15 years)
Growth rate: moderate or slow
Coppicing ability: vigorous, responds to pruning, pollarding
Erosion control potential: excellent for sandy sites
Root system: moderate to deep
Shade tolerance: grows best in full sunlight
Wood density: mod. to high (greater than 600 kg/cubic metre)
Carbon sequestration potential: low
Uses
Specialty products: good for honey, pollen has value, leaves are a source of cineole
Urban use: suitable as a screen or hedge
Wildlife value: flowers are especially attractive to birds
Wood products: broombush fencing
Potentially undesirable attributes
Growth habit: shallow roots may outcompete adjacent plants
Weediness: high potential based on its biology

References

[1] Craven, LA, Lepschi, BJ, Broadhurst, LM, Byrne, MB. (2004) Taxonomic revision of the broombush complex in Western Australia (Myrtaceae, Melaleuca uncinata s.l.). Australian Systematic Botany, 17: 255-271.

[2] Gunn BV (2001) Australian Tree Seed Centre Operations Manual. Internal Publication, CSIRO Australian Tree Seed Centre, ACT. [Online at http://www.ensisjv.com/Portals/0/atsc-opmanualcomplete.pdf  Accessed March 2008]

[3] Western Australian Department of Agriculture and Food online: http://www.agric.wa.gov.au/content/lwe/vegt/trees/fs02500.pdf

[4] Primary Industries and Resources South Australia Fact Sheet online: http://www.pir.sa.gov.au/__data/assets/pdf_file/0007/37852/Broombush_for_Brush_Fencing.pdf

[5] Marcar NE, Crawford DF (2004) Trees for Saline Landscapes. RIRDC Publication Number 03/108, Canberra.

Internet links

eFloraSA Electronic Flora of South Australia: http://www.flora.sa.gov.au/cgi-bin/texhtml.cgi?form=speciesfacts&family=&genus=Melaleuca&species=uncinata&iname=&submit=Search

Greening Australia: http://live.greeningaustralia.org.au/NR/rdonlyres/9F76AB5F-5951-4BBF-A99F-98ADBCC5BC1C/2550/Broombush4.pdf

Primary Industries and Resources South Australia Fact Sheet: http://www.pir.sa.gov.au/data/assets/pdf_file/0007/37852/Broombush_for_Brush_Fencing.pdf

Victorian Department of Primary Industries: http://www.dpi.vic.gov.au/ [search site for relevant documents]

Western Australian Department of Agriculture and Food: http://www.agric.wa.gov.au/content/lwe/vegt/trees/fs02500.pdf

Top