|Rural Industries Research & Development Corporation|
Welcome to the BANKSIAS (CUT FLOWERS) chapter of RIRDC's major new publication (contents page here) on nearly 100 new rural industries.
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by Margaret Sedgley*
Banksias are identified internationally as Australian, and this is an important selling point which can be exploited on overseas markets. In addition to their visual attributes, they have other features which will ensure their continued popularity, including long shelf life and variety of colour and form.
The main constraint to industry development is the lack of cohesion in the cut flower industry, and the reluctance to communicate and co-operate. Commercial species of banksias are native to mediterranean climate areas, and thrive in light sandy soils of acid pH. This is probably the greatest current production constraint. Banksias are widely cultivated for cut-flower production in southern Australia, with some production in Israel, South Africa, Hawaii and California.
Export of fresh cut flowers is the area with most potential for expansion. The current annual export value of banksias is approximately A$1 million, with half of the production from Western Australia. The largest export destination for fresh flowers is Japan. Germany takes fresh and dried product.
The most important personal skill requirement for the banksia industry, is recognition of the intensive nature of production. Plant care is essential for quality production and hence for success. Cultivation of banksias must be encouraged in place of bush picking.
The industry is very fragmented, thus placing the individual grower in a weak negotiating position. Most growers of fresh and dried banksias sell to a wholesaler or exporter, although some deal directly with domestic retailers or with overseas importers. Quality standards are currently under development.
Export of fresh cut flowers is the most important and lucrative side of the industry, although some fresh material is sold on the domestic market. There is a smaller demand for dried or dyed blooms, for foliage and for cones. This market is less demanding and generally takes the second grade material unsuitable for the fresh market. For all export markets the quietest demand period is between January and March. Costs of export are high and include costs at the destination, air freight, packaging and quarantine inspection.
The most important export destination is Japan, whose market will pay between $1 and $2.50 per stem. This market is still expanding, as are many other Asian and European markets. Bloom preferences of the various export destinations are important. The USA, Taiwan and Hong Kong prefer dyed banksias, European markets prefer natural colours, and the Japanese like soft, subtle pastels. Most exports to Germany are orange banksias, with 慳utumn colours�, which are popular for the All Saints festival in November and for grave decoration.
Banksias require a mediterranean climate with high light intensity and long hours of sunshine, low relative humidity and absence of frosts, although some species can tolerate temperatures down to �deg;C for short periods. These conditions occur in the coastal areas of southern Australia (see map). Banksias are adapted to soils of low nutritional status, particularly phosphorus, and have a requirement for well-drained acid sands.
Irrigation should be provided throughout the life of the plant, with drip irrigation or microjets the most efficient in terms of water use. Tensiometer studies indicate that, in Australia, irrigation is necessary in all except the winter months. Most of the banksia root system is in the top 15 cm of soil, so regular irrigation is advisable. The plant also has tap roots and vertical sinkers, which can reach down to 7 m to access groundwater. Most banksia growers irrigate twice per week, or three times per week during hot spells. Commonly 4 L/hour drippers are used and irrigations are for 2�hours.
The most widely cultivated species in Australia are the scarlet Banksia coccinea, the orange B. prionotes, B. hookeriana, B. burdettii and B. victoriae, the green/yellow B. baxteri and B. speciosa and the pink B. menziesii. In Israel, the orange species B. ashbyi is widely cultivated. Other species cultivated to a lesser extent are B. occidentalis, B. grandis, B. sceptrum, B. solandri, B. ericifolia, B. integrifolia and B. brownii.
There are three named cultivars for cut flower production. 慦aite Orange� is a natural interspecific hybrid between B. hookeriana and B. prionotes, which flowers between the peak period of the two parental species and so extends the season for production of orange blooms. 慦aite Crimson� is a mid-season dark red selection of B. coccinea, and 慦aite Flame� is an early season orange-red selection, also of B. coccinea. All are currently being multiplied, and should be available for sale in 1998 from Proteaflora Pty Ltd in Victoria.
Most banksias are propagated via seed collected from the native habitat, but there is an increasing trend toward cultivated seed sources, and vegetative propagation using rooted cuttings. The useful plant life is roughly 10 years. Average yields vary with species from 60 flowers/plant for B. menziesii up to over 100 for B. baxteri.
Planting is generally done in autumn for
the best results, and the area should be cleared of weeds in advance. Between-plant
spacings may be 1�m for the upright B. coccinea to 3.5 m for the
more spreading species such as B. speciosa and B. prionotes.
Between row spacings vary between 3 and
6.5 m. Windbreaks are advisable to protect the young plants from damage, and a mulch of a freely-draining medium such as gravel, coarse sand or organic material aids in protection of the roots from extremes of temperature. Weeds should be cleared continually from around the plant, but care must be taken with herbicides because banksia roots are near the surface.
Nitrogen, potassium and iron are important nutrients, but high levels of phosphorus are generally avoided. Fertiliser rates used in Australian flower farms vary enormously, but healthy growth has been recorded with 0.5 g urea plus 0.5 g potassium chloride applied per plant through the irrigation system every 6 weeks, with 1 g ammonium nitrate and 1 g potassium sulphate per week during the active growth and flowering period. Alternatives to potassium chloride should be used where irrigation water is of poor quality, iron chelate is applied when chlorosis is a problem, and calcium nutrition may be an issue in older plants.
Training and pruning of banksias is commenced early and continued throughout the life of the plant. Within a year of planting, the main stem is pruned back to encourage three or four strong, low scaffold branches, which have wide crotch angles and are well spaced around the plant. These are headed back the next year to encourage further branching to form a rounded canopy. At harvest, the blooms are removed leaving four or five healthy leaves below the cut. Immediately following harvest, all thin shoots are removed flush with the stem. This is also the time to remove all two-year-old shoots which have not produced a bloom, once again leaving four or five healthy leaves below the cut so that new branches will form for future harvests. In Western Australia some growers use a hedge trimmer rotation every two or three years. Banksias produce their first crops after 4 years from seed and 3 years from cuttings.
Phytophthora cinnamomi, which causes root rot, collar rot or dieback, is the most devastating disease of banksias, as it can result in widespread loss of plants in the field, and can prevent successful replanting in affected areas. The disease is soil-borne, and is readily transmitted on feet, vehicles and tools. It is also transmitted by water, and plants dying successively down a hillside following heavy rain is characteristic of Phytophthora infection. Poor growth is followed by drying and wilting of the foliage, as by the time above ground symptoms are visible, the root system has been heavily colonised. In addition to dead roots, there is often stem (collar) rot at ground level. Control of Phytophthora is very difficult. Introduction of the disease to a new planting must be avoided, as it is impossible to eradicate the disease once it is established, and it can survive in soil without a host for many years. Chemicals which have been used against Phytophthora include phosphonate, fosetyl Al, phosphonate and furalaxyl, but the chemicals may adversely affect banksia plants.
Aerial canker diseases caused by a group of fungi including Diplodena are an increasing problem in Western Australia. They can be controlled using clean secateurs and Carbendazin.
Scab or corky bark (Elsinoe spp.) causes red, raised scab like lesions on the stems and leaves, which subsequently become corky, and distort growth of the branches. The disease is favoured by moist conditions and moderate temperatures, and it may remain latent in the plant. Removal and destruction of infected material is important. Chemicals which have been used against the disease include mancozeb, prochloraz MnCl2 complex and benomyl.
Tunnelling moth larvae (Arotrophora spp.) feed on the flowers. The adult moth lays its eggs on immature blooms and the caterpillars feed on the developing flowers. They move into the centre of the bloom and kill large numbers of flowers by feeding on the soft tissue. The larva pupates in the flower stem. Control is difficult as the larva is protected within the stem, and removal and destruction of infested blooms is essential.
Banksias are harvested by hand with sharp, clean secateurs to minimise stem damage, and placed into clean water or preservative solution during the coolest part of the day. Care must be taken to avoid bruising and damage to the blooms. The leaves are generally hand or machine stripped from the lower 10 cm of the stem, and in some cases from around the bloom. Blooms are graded according to stem length and quality. Sucrose pulsing does not enhance quality or longevity, and concentrations above 2% are detrimental. B. coccinea blooms have a vase life of 15 days in water plus 0.01% chlorine. Hydroxy quinoline sulphate is detrimental. Cold dry storage is possible at 2°C and 100% relative humidity in darkness for 14 days, after which there is a 10 day vase life.
For natural drying, the blooms are hung until dried, and the process can be accelerated by solar heating, hot air dryers, dehumidifiers, microwaving, freezing and dehydration using silica gel. The colours of both flowers and leaves fade under these conditions. Sulphuring to preserve the colour is achieved either by burning elemental sulphur or by using sulphur dioxide gas in an enclosed area. Stems can be bleached using hypochlorite, chlorite, peroxide or hydrosulphite.
Blooms of pale species can be coloured by dipping into aniline or water-soluble dyes. These impart a wide range of bright colours including blue, purple, orange, red and green, or combinations. Uptake dyes produce more subtle colours but are not much used. Costs of drying and processing are of the order of $0.30/bunch for drying or dyeing, and $0.90/bunch for preserving.
All live insects must be removed from fresh cut flowers before export. Disinfestation methods generally involve chemical control using methyl bromide, dichlorvos, pyrethrin, permethrim or deltamethrin. Fungicide dips are sometimes used to control postharvest development of grey mould caused by Botrytis cinerea.
Cool facilities and rapid transport are essential throughout the marketing chain. The carton should be robust, recyclable, and attractive and display information on variety, supplier and grade. Size requirements differ for the various markets, and the supplier must ensure that the carton size is compatible with containers and pallets in the port of delivery. Liners are sometimes used in the carton. Forced air cooling is ideal, and the carton should have ventilation holes to allow air flow. Refrigerated transport and cool rooms at the point of dispatch and receipt are important.
Economic analyses for new crops should be treated with caution, especially as so many banksia growers produce other crops as well. Indicative figures are that a 5�ha cultivated unit is considered the minimum to provide a full-time family living. This represents a minimum investment in the order of $500,000, including the cost of land, cultivation, plants, irrigation, buildings and improvements and machinery. Plant costs alone can amount to over $3000/ha, with irrigation costs up to $3400/ha. Efficiency rises for a larger farm with economy of scale.
Annual per hectare expenses for a banksia farm are estimated at $300 for replacement plants, $150 for weedicides, $375 for pesticides, $100 for power, $100 for water, $150 for fertiliser, $3000 for labour, $1650 for machinery hire, $250 for fuel, $3000 harvesting costs and $3000 pruning costs. First grade blooms will return $0.60 per stem, second grade $0.40 and third grade $0.25. Overall annual expenses for a banksia enterprise are of the order of $12,075/ ha, against income of $20,119, with a gross margin of $8044/ha.
Department of Horticulture, Viticulture and Oenology
Waite Agricultural Research Institute
The University of Adelaide
Glen Osmond, SA 5064
Phone: (08) 8303 7242/7248
Fax: (08) 8303 7116
Primary Industries South Australia
Phone: (08) 8389 8800
Agriculture Western Australia
Albany, WA 6330
Phone: (08) 98 928 444
Fax: (08) 9841 2707
P.O. Box 145
Kingswood, SA 5062
Phone: (08) 9373 2488
Fax: (08) 8373 2442
AF&PGA (Australian Flora and Protea Growers Association)
Frogmore, NSW 2586
Phone: (02) 6385 6222
FECA (Flower Export Council of Australia)
P.O. Box 137
Nedlands, WA 6009
Phone: (09) 327 5563
Fax: (09) 327 5683
Proteaflora Nursery Pty Ltd
P.O. Box 252
Monbulk, Vic 3793
Phone: (03) 9756 7233
Fax: (03) 9756 6948
Barth, G. E. 1992. Banksias for cut flower production. Factsheet, Department of Agriculture, South Australia, Agdex 280/11.
Karingal Consultants 1994. The Australian wildflower and native plants cutflowers and foliage industry: a review. RIRDC.
Primary Industries South Australia/South Australian Research and Development Institute 1995. South Australian Ornamentals Industry Development Plan 1995�00.
Sedgley, M. 1996. Banksia. In: Horticulture of Australian Native Plants and Their Uses. Eds. K. Johnson and M. Burchett, New South Wales University Press. Chapter 3, 18�.
Webb, M. 1996. Banksias for cut flower
production. Agriculture Western Australia Farmnote,
|Margaret Sedgley is Professor of Horticultural Science at
the University of Adelaide, Department of Horticulture, Viticulture and
Oenology. She has worked on improvement of native plants for ornamental
horticulture for over 15 years.
For address see Key contacts.
Last updated: 10 january 1998
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