The
              Report

No. 108: Cultivation of Golden Cascade will boost cutfower exports to Japan


The full report
This Short Report is a summary of a full report Cutflower Production of Golden Cascade, RIRDC Publication Number 01/157, UWA- 46A, by Dr K.A. Seaton, Horticultural Science Plant Research and Development Services, Agriculture Western Australia, Phone: 08 9368 3244, Fax: 08 9367 2625. The full report is available in hardcopy for $10 from RIRDC (ph: 02 6272 4819 or from our eshop) or can be downloaded for free from RIRDC’s website: www.rirdc.gov.au/fullreports/wnp.html

New propagation and cultivation techniques could boost exports of the valuable but difficult to manage wildflower, Golden cascade (Corynathera flava) – a unique species indigenous to a small region of midwest of Western Australia.

The project, undertaken by Agriculture Western Australia’s Dr Kevin Seaton, was funded by the Rural Industries Research and Development Corporation (RIRDC) as part of its Wildflower and Native Plants R&D Program.

Dr Seaton reported to RIRDC that the project offers increased opportunities for marketing a regular supply of the wildflowers with consistent quality.

But it will involve strict propagation and cultivation protocols that producers will need to evaluate to determine profitability.

Golden cascade is valued for its long whispery clusters of small golden yellow flowers. Flowering from October to February, it is particularly sought after as a cutflower around Christmas.

Previously Corynathera flava has been predominantly bush picked with about 150,000 stems now sold annually – most of them exported to Japan.

The work involved developing a complete package, including selection, propagation, field production systems and postharvest handling methods.

The project

The objective was to provide the wildflower industry with a new, unusual and potentially highly profitable cut flower.

This involved studying the biology of Golden cascade in its natural environment, selecting commercially desirable forms and developing methods for establishing and cultivating the wildflower in commercial cut flower production.

Surveys of natural populations yielded information on the plant’s population dynamics and provided a basis for making informed conservation judgements. The work also is directly relevant to developing other valuable but difficult to manage wildflowers.

The surveys, carried out in association with the Department of Conservation and Land Management (CALM), indicated picking of Corynanthera flava from private property was sustainable providing certain procedures were followed.

Currently licenses are issued when CALM is satisfied that picking is sustainable and no more than 20 per cent of plants in a population are removed. CALM also requires green stems to be left below where the plant is cut and for property burns to occur not more than once every eight years.

Stem harvest was high in 1995 (more than 200,000 stems) before restrictions were introduced on harvesting. For the next couple of years harvesting was reduced to around 100,000 stems. But by 1999, as shown in the graph below, 175,000 stems were being harvested.

In the propagation research, selections from natural Golden Cascade populations were made over two seasons. The approach involved:

Cutting methods aimed to determine hormone type, the concentration and quality, and type of plant material most suited. Tissue culture sought to determine methods of multiplication in culture, root initiation, deflasking and establishment in potting media.

The results

Cutting propagation trials identified one variety (and possibly another) which produced a high strike rate of 70 per cent compared with the rest which had poor strike rates below 30 per cent.

Tissue culture methods were successful in introducing seven selections selected from wild populations into culture. The research identified specific culture environment, media and hormone levels suited to Golden cascade propagation. Plant survival following tissue culture was low, with root systems failing to become established in the nursery. Some selections were identified as better able to survive “potting on” from tissue culture.

A protocol was developed cultivating the wildflower along with effective methods of irrigation. Postharvest handling was investigated and a selection identified with a 26 per cent longer vase life.

During the early stages of the project there were concerns about the long-term sustainability of picking this wildflower from natural populations. But a suggestion of banning bush picking was averted.

A key finding was the need to leave green shoots below where plants were cut for stems.

When they were cut to bare wood the plants generally fail to regenerate.

Another finding was that, on average, only 20 per cent of stems should be picked in one area in a season. This is important as field surveys indicate that Corynanthera flava is slow growing in the bush, taking a number of years to regenerate.

The challenges in successfully propagating plant material from the wild are to develop reliable propagation methods and to establish irrigation and fertiliser protocols to maintain plants in cultivation. There are no precedents from other wildflowers on tackling these problems. Golden cascade’s closest successfully cultivated relative is the Geraldton waxflower which is much easier to bring into cultivation.

Golden cascades appear to grow best when planted under micro sprinkler irrigation in bare soil in spring without a mulch. Occurring naturally on sand over gravel, growing this plant on deep sand poses a challenge for irrigation management. Managing the water demand of plants on deep sand involves ensuring plants are adequately but not over watered. This also prevents wasting water.

The vase life of selections of Corynanthera flava is adequate without the requirement for special postharvest vase solution treatments.

Some petal drop occurs apparently involving the older petals. The good packing density of this flower provides a freight advantage.


The propagation and cultivation methods defined in this project will provide the cut flower industry with an opportunity to commercialise this valuable wildflower.

Commercial production of Corynanthera flava will require following appropriate protocols, particularly those for field management to ensure best growing results. Propagators will need to pay special attention to detail and quality control.

They also will need to decide whether this crop is sufficiently economical to warrant such effort and expense.

Predetermining when to start irrigating is also critical as it avoids over watering which can kill many wildflowers. Water savings of 30-50 per cent can also be made using this method without causing the plant to wilt.

The robust postharvest characteristics of Corynanthera flava, especially its insensitivity to ethylene, makes handling easy. Also the good pack out of the stems offers considerable freight advantage.


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