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Will the Waratah Ever Fulfil its Potential?

Jolyon Burnett

The New South Wales waratah (Telopea speciosissima) has many attributes that make it an ideal candidate for both a home garden staple and a specialty cut flower crop. The waratah is the floral emblem of New South Wales and is identified internationally as an Australian symbol. There is already a high degree of "consumer awareness" and little extra promotion will be needed for its growth as domestic nursery product and the expansion of the waratah as a commercial cut flower the export markets. Market research on the suitability of Australian native blooms for export as cut-flowers (Lamont, 1982) has shown that there is greatest demand for "erect, compact, terminal inflorescences with a strong 3D shape". Also identified was an "insatiable" demand for blooms of all shades of red, the deeper the better, especially when complemented by dark green foliage. The plant is long-lived, it regrows from the lignotuber after cutting and it can produce up to sixty blooms per plant per year (Loftus, pers. comm.). This could translate to up to 20,000 to 50,000 blooms per ha. (Worrall, 1993, unpub.). The waratah inflorescence has a long vase life and there is the possibility of an extended storage period for the cut flower (Rogers, 1973).

New South Wales waratah Telopea speciosissima in its natural habitat on the central coast of New South Wales. Select the thumbnail image or plant name for a higher resolution image (32k).

Development as a Horticultural Product

Despite all the predictions and promising rhetoric the waratah "remains a novelty in the home garden and a marginal cut flower crop. Much development work is still needed to establish the waratah as a successful commercial product both in home gardens and as a cut flower. Dependable cultivation, large scale production, and reliable and reproducible quality of blooms are necessary; in short a large amount of research over a long period is needed to turn a wild flower into a commercial product. The waratah still has a reputation as a difficult and short-lived garden plant and it has not been widely cultivated. To my knowledge it has never been used in a commercially designed landscape despite its undoubted symbolic and aesthetic qualities. The APGA estimates national production of waratah at around 1.7 million stems annually (Worrall, 1993, unpub.). While approximately 90% of all waratahs sold at Sydney's Flemington markets ten years ago were bush-picked (Lynch, pers. comm.), in 1993 as many as 50% may come from Victoria (mainly one plantation in the Dandenongs). Of the limited cultivation occurring in New South Wales most holdings are less than one hectare although the growth in sales at Flemington is running at around 10% a year.

Propagation

Seeds of waratah germinate easily (Worrall, 1983; Anon, 1976). Provided the seed is fresh and is treated with a broad spectrum fungicide germination rates of 80% can regularly be obtained. There is great variation in seedling populations of waratah. Plantations which have been planted with seedlings exhibit wide variation in the growth habits of plants, in bloom characteristics and in plant vigour. This variation, although undesirable from a floricultural viewpoint, offers the opportunity to select high yielding clones or to select plants with particular bloom characteristics. Much greater effort should be directed towards screening large seedling populations for improved cultural characteristics rather than novel bloom colour or shape as has largely been the case to date.

For the home garden seed from vigorous plantation specimens should ensure tolerance of cultural conditions. For commercial plantations clonal material of selected genotypes is required to properly exploit the market. Worrall (1976) has shown that strike rates of nearly 100% can be obtained from hardwood cuttings taken in spring. Nixon (pers. comm.) has had some success with single node cuttings. All four species of waratah - Telopea speciosissima, T.truncata, T.mongaensis and T.oreades - are graft-compatible. Rootstock and scion combinations are used for many woody perennials to provide the necessary mix of floral or fruit characteristics and cultural requirements. The Israelis (Ben-Jaacov, et al, 1988) are looking to exploit this compatibility to improve tolerance of a range of soil conditions. Further work will be needed to overcome the habit of regrowth from the lignotuber but for the home garden this may be the approach for weak clones such as the white variant.

The work of Offord and Campbell (1992, a & b) and others has shown that waratahs can be successfully propagated by tissue culture with multiplication rates of three to six times using a modified Murashige and Skoog medium. However; different clones require different optimal culture conditions meaning that developmental work would be needed for each clone. The more substantial problem appears to lie in hardening off, with roots and leaves produced in vivo dying off on planting out (Offord et al., 1990). Indications are that air filled porosity is critical for this process. Recent work in New Zealand (Burge, pers. comm.) may have developed a technique to overcome this.

Establishment and Culture

The great majority of cultural problems with waratahs are associated with soil conditions and excellent drainage and adequate air filled porosity are essential. While in Australia we have concentrated on manipulation of the soil environment (Burnett and Mullins, 1987), the Israelis (Ben-Jacccov et al, 1988) are investigating methods of avoiding these problems (grow bags, plastic lined trenches) or tolerating them (rootstocks, breeding). Early spring or early autumn are the best times for transplanting material to the field. but there is some disagreement as to the best material to use. Aust-flower, Australia's largest commercial waratah plantation, at Gembrook, Victoria, use seedlings and transplant them to the field within six months of germination. Nichols (pers. comm.) maintains that this allows the seedling to harden off in situ, that this procedure is the cheapest method for plantation establishment and that survival rates of 90% can be obtained. The University of Sydney, has shown that well established plants are the best materials for planting-out in the field. An advantage of cuttings is that the first blooms are potentially produced within two years of planting-out but seedlings come into flower after three to five years. Transplants must be staked or protected by wind breaks because damage at ground level due to movement in the wind has been identified as a cause of transplanting mortality.

A superb flowering stem of Telopea speciosissima. Select the thumbnail image or plant name for a higher resolution image (33k).

Telopea speciosissima "Wirrimbirra White" is an unusual variant which has become more widely available in recent years. Select the thumbnail image or plant name for a higher resolution image (32k).

Specht (1978) has shown that many native plants have poor establishment in soils with high levels of nitrogen and phosphorus. This may explain why fertiliser application immediately after the transplanting of waratahs in the field often leads to high mortalities. In general, the waratah appears to be a "gross feeder". Goodwin (1973), Worrall (unpub.) and Nichols and Beardsell (1981 b) have all reported a strong growth response to high nutrient levels. The details of this response are not year clear. Grose (1989) found a clear response curve for phosphorus with an optimal growth level of 3.1 mg P/kg soil. The amount of phosphate received by seedlings had no effect on the partitioning of dry weight between shoot and root. Goodwin has suggested that the plant is phosphorus-sensitive (i.e. levels of 1.26 g/l of potting medium are toxic) but Worrall claims that pot-grown waratahs respond well to high phosphorus levels (i.e. levels of 0.56 g/l of potting medium). Both reported a complex phosphorus/nitrogen interrelationship. Work by Specht (1963), on related species, indicates that fertiliser application may hasten maturation and give early flowering.

Pruning and Irrigation

There has still been no systematic work on either of these management factors. Pruning is of great importance to successful commercial cultivation of waratahs although most home garden cultivation still revolves around benign neglect. The aim of pruning is to produce a tree that will carry a maximum number of blooms. The waratah produces terminal blooms on one-year wood. The previous seasons must be removed to approximately 5cm to encourage the out growth of basal shoots to renew the flowering wood. Bloom picking and pruning should be done in the one operation as pruning later than January may remove initiated inflorescences. Common wisdom is that drip or trickle irrigation is more suitable for waratah cultivation than overhead sprinklers. Certainly trickle irrigation gives more effective water delivery, less weed growth, less likelihood of water-logging and better control of scale and soil-borne pathogens than overhead irrigation. It should be noted, however, that waratahs have been successfully cultivated for twenty years without irrigation at Rylstone, NSW, an area in which the annual rainfall is less than 700mm.

Pest and Disease Control

Greenhalgh and Maughan (1983) identified Colletotrichum sp. as pathogens of waratah, and work at the University of Sydney has shown that Pythium sp. and Rhizoctonia sp. are also virulent pathogens. Phytophthora sp. infections can lead to "sudden death" of waratah plants, particularly under conditions of impeded drainage and temperatures of 20-30^oC and Summerell et .al (1990) found Cylindrocapon destructans to be involved in similar symptoms. As most root-rot pathogens cause similar symptoms in the aerial portions of waratah plants the identification of the casual organism is often difficult and regular preventative application of systemic fungicides are strongly recommended. Pests of cultivated waratahs included scale (Chionaspis eugeniae) and the larvae of a moth of the family Xyloryctidae, known commonly as "Waratah Bud Borer". The latter is particularly troublesome because it bores into the terminal buds during winter and destroys the inflorescences. Austflower has experienced problems with the ringbarking of young plants by weevils (Phlctrin callosus) and field crickets (Gryidae). At the University of Sydney plantation minor damage was caused by parrots feeding on terminal buds.

There may be real scope for the use of integrated pest management on waratah. Bush picked stems coming from an environment of relatively undisturbed pest and predator relationships are on average significantly less affected by bract browning and pest damage. It is somewhat ironic that many commercial plantations have ended up using routine preventative pesticide application for what was intended to be a low maintenance crop. Recent work by Bellgard (1991) confirming vesicular-arbuscular mycorrhizae associations in natural waratah stands may be important in this regard.

Extension of Flowering Time and Genetic Improvement

Some work has been done on the reproductive anatomy and the regulation of flowering of the waratah, although this has been far from conclusive. Extension of flowering times through cultural or chemical treatments remains a distant possibility and coordinated production across a range of latitudes remains the best chance of extended marketing times. Flowering may start as early as August in northern NSW and extend until early December in Tasmania. Despite considerable media attention New Zealand produced blooms are likely to compete only with those produced in Victoria.

Telopea "Braidwood Brilliant" is a hybrid between T.speciosissima and T.mongaensis. Select the thumbnail image or plant name for a higher resolution image (38k). Photo: Australian National Botanic Gardens

Due to the large variation within T.speciosissima the emphasis so far in genetic improvement has been on clonal selection rather than on hybridisation. However this selection has been based on anecdotal reports of superior bloom characteristics and less commonly increased plant vigour. The University of Sydney, the National Botanic Gardens, Canberra, Wirrianda Nursery in NSW, and both Duncan and Davies Nursery and Levin Research Station in New Zealand have commercial releases or PVR on waratah. But there has been no thorough screening for tolerance of the various soil environmental conditions and pathogens that limit the plants potential in almost every situation.

Until the problems associated with hardening off tissue cultured plants has been overcome the limited amount of material of improved selections is barely sufficient for further research let alone commercial plantations.

Postharvest

The NSW waratah has a vase life of approximately two weeks while for the most common hybrid, T.speciosissima x T.oreades, it drops to around one week. They can be stored at 1^oC for up to 3 weeks (Worrall, 1993, unpub.) with approximately a 30% reduction in subsequent vase life. To date a wide range of floral preservatives have shown no extension of vase life.

Conclusion

The development of the waratah as a garden staple or as a cut flower crop will be a long term undertaking. Attempts to promote the plant as a finished product in the mean time may be counter-productive as was seen with native plants in general in the 1970s. However, given its unique profile careful promotion as a specialty item can help to build interest as development progresses. The development of such methods for the commercial cultivation of the waratah is a vital contribution to the understand and conservation of this unique native species. The harvesting of flowers from the wild to satisfy public demand for the waratah as a cut flower and continued urban development in the area of natural occurrence are placing increasing pressure on natural stands.

However, until some proprietary interest is developed through registered cultivars an effective promotion of the waratah is unlikely and its use as a garden shrub will remain minor. As a cut flower the prospects are slightly more encouraging but will depend as Worrall (1993) suggests on the continued expansion of protea growing and export marketing and the intelligent diversification by growers into appropriate counter-season crops and filler lines.

Acknowledgements

This paper has been compiled, in part, from information and papers kindly supplied by Ross Worrall, Brett Summerell, Cathy Offord and Susan Alexander. My appreciation also to Paul Nixon for his unassuming depth of knowledge.

References

This article is a reproduction of a paper presented at the SGAP 17th Biennial Seminar, Sydney, New South Wales, 27 September - 1 October 1993.

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Australian Plants online - June 1999
Association of Societies for Growing Australian Plants