Rural Industries Research & Development Corporation

The New Rural Industries
A handbook for Farmers and Investors

Welcome to the EUCALYPTS chapter of RIRDC's major new publication (contents page here) on nearly 100 new rural industries.

Eucalypts
(Cut flowers and foliage)

Introduction

Eucalypt foliage has been cultivated for many years in southern France, Italy and the USA. The market is based upon the attractive juvenile growth of species with round or oval waxy leaves which have a silvery sheen.

Once the tree attains the adult state, the foliage assumes the green, elongated leaf form and its value for foliage stems falls. Recently, however, a market has developed for adult material which has reached the flowering stage. The buds, open flowers and gumnuts of a number of eucalypt species have become the basis of a cut floral stem trade.

With over 500 species, the genus has wide adaptation to temperate, subtropical and tropical climates. Eucalypts are tolerant of most soil types and have a range of uses. In addition to cut flowers and foliage, they are used for amenity horticulture, timber, pulpwood, fuelwood, shelter belts, soil amelioration, honey production and water-table lowering.

The main constraint to industry development is lack of cohesion in the cut flower and foliage industry, and reluctance to communicate and co-operate. A further constraint is the lack of superior cultivars in Australia, which results in lack of uniformity in yield and quality of product.

Export of fresh cut flowers and foliage is the area with most potential for expansion. The most important personal skill requirement for the eucalypt flower and foliage industry, is recognition of the intensive nature of production. Plant care is essential for quality production and hence for success.

Markets and marketing issues

Stems are sold on both domestic and export markets. High quality and long stem length are important for the lucrative export market, and Australian exporters deal directly with Japanese importers. Stems are packed into florist size boxes for direct sales and through the auction system. Further niche markets for Australian product have been identified in other Asian countries, Europe, USA and Canada. Buds and foliage are handled through these channels. The best period for sending product to Japan is from October to April when supply from northern hemisphere countries is in short supply. Common names have been developed for some of the species to aid in market identification.

Production requirements

Most current production is in coastal areas (see map). Of the 500 plus species of Eucalyptus, there are some adapted to all climates such that production is potentially possible throughout Australia. Frost tolerance also varies widely. Most species require a minimum of 200 mm rainfall per year, and many growers supply drip irrigation to ensure reliable production levels. Regular watering is especially important during spring and summer. Soil type, salinity and pH tolerance vary widely across the genus, with species adapted to most areas across Australia.

Varieties

The main species grown for foliage production are E. gunnii, E. pulverulenta and E. cinerea. Many others have potential for foliage production, including E. albida, E. bridgesiana, E. cordata, E. crenulata, E. crucis, E. gillii, E. globulus, E. kruseana, E. perriniana and E. tetragona. Species for bud and flower production include E. caesia, E. crucis, E. erythrocorys, E. forrestiana, E. leptophylla, E. lesouefii, E. pyriformis, E. stoatei, E. tetragona, E. uncinata, E. yalatensis and E. youngiana. Further work is needed to determine the best species for cultivation in different areas, and not all have been fully tested in the marketplace. There are no superior eucalypt varieties for flower or foliage production available in Australia.

Agronomy

Plantings are established using seedling material, although vegetative propagation via rooted cuttings and grafting is possible for some species. Seedlings are planted out when they are 30 cm high. Planting is done in spring or autumn, and the land should be deep ripped to 30–50 cm a few months before planting when the soil is moist and friable.

Spacing varies from 1.5 to 3 m within and between rows, depending on plant size and end use. Wide spacing avoids reduction of flower initiation for floral stems, whereas 30 cm within-row spacings are sometimes used for intensive foliage production. Some growers use mounded beds to increase aeration of the root zone, drainage and salt leaching, or contour banks to avoid erosion on slopes.

Weed mat can be used, and black plastic also increases root-zone temperature. Tree guards are advisable in areas where rabbits are a problem. Dolomite or lime improves establishment in acid soils, and sulphur serves the same purpose in alkaline soils. Fertiliser is often applied via the irrigation system, although top dressing is advisable on sandy soils to avoid leaching. In frost-prone areas, nitrogen should be avoided after mid summer, as the new growth may burn before it hardens off.

Eucalypts benefit from regular applications of complete fertiliser, including trace elements, and this can be applied via organic or inorganic preparations. Nutrient deficiencies are common if harvesting is regular and fertiliser application is inadequate: common symptoms include chlorosis, leaf spot and purpling.

Pruning is essential for optimum production, but differs depending on the end use of the crop. For foliage production, the tree must be heavily pruned to maintain juvenile leaves and encourage long stem length. At 18 months of age, the main stem is pruned to one metre and major lateral branches are removed flush with the trunk.

Stems for harvest derive from buds under the bark of the trunk on of the basal swelling or lignotuber. In temperate climates, pruning in late winter stimulates stems for harvest in late summer, and trees are pruned annually.

More flexibility is possible in frost free and tropical climates, where irrigation can be used to control production and vary harvest time. High foliage yields are produced by E. globulus and E. bridgesiana. Average yields for most species are 10 bunches per tree, of 10–12 stems 65–70 cm in length, at 3 years of age.

For bud, flower or gumnut production, the plant must attain the adult state, so pruning is less severe. The tree should be pruned before one year old to stimulate branching and create maximum shoots for flower initiation. At harvest, some leaves should be left below the cut to provide further branches for flower production.

Pest and disease control

A wide range of insect pests attacks eucalypts, including sawfly larvae (Perga), leaf miners (Perthida, Phylacteophaga), sucking insects (Creiis, Eriococcus, Cercopidae) borers (Cerambycidae, Phoracantha), gall forming insects (Apiomorphinae, Strongylorrhinus), mites, caterpillars (Uraba, Mnesampela, Doratifera, Oenochroma), beetles (Catasarcus, Liparetrus, Chrysomelidae, Paropsis) and grasshoppers. The leaf-eating beetle Paropsis can quickly defoliate plants. Pests can be controlled with a range of standard insecticides.

The most devastating disease of eucalypts is Phytophthora cinnamomi, which causes root rot. Care must be taken to avoid introduction of the disease, as eradication is impossible. If a property is infected, then tolerant species should be grown, such as E. cinerea, E. cordata, E. crenulata, E. globulus, E. gunnii, E. perriniana and E. pulverulenta. Phytophthora-sensitive species, such as E. caesia, E. crucis, E. erythrocorys, E. forrestiana, E. kruseana and E. tetragona, should be avoided.

Leaf spot and shoot blight fungi can cause problems in eucalypt plantings, particularly in humid climates. Fungi involved include Phoma, Microsphaeropsis, Mycosphaerella, Colletotrichum, Botrytis, Stemphylium and Alternaria. They can be controlled using standard fungicides.

Harvest, handling and postharvest treatments

Stems should be harvested into water during the coolest part of the day, and recut under water. The leaves are carefully stripped from the basal 15 cm of the stem. Stems may be dipped into anti-transpirants to reduce water loss. Holding solutions of 2% sucrose with germicide are beneficial in extending vase life, but pulsing has no effect. Stems have a vase life of 2 weeks when kept in holding solution, or 1 week following dry transport. Stems should be dry before packing, and box liners are often used.

Eucalyptus foliage is sometimes preserved using glycerine. This gives an attractive sheen and supple texture. One part of glycerine is mixed with two parts of water, and stems will take up the mixture over a period of up to a week, or they can be immersed in a more concentrated solution. Dyes can be used to colour the foliage. The stems are then hung to dry.

Stems for export must be free of pests. Stems with gumnuts are generally sold on the domestic market as seed feeders are difficult to eradicate.

Economics of production and processing

Economic analyses for new crops should be treated with caution, especially as so many eucalypt growers produce other crops as well. For a foliage farm in South Australia, producing more than 500,000 blooms per year and receiving a price per stem of $0.25, the gross farm income in 1995 was $137, 213 for average yields and $151,073 for above average yields. This represents a farm profit of $31,261 for average yields and $45,121 for above average yields, with a return on capital of 6.6% and 9.5%, respectively.

Annual expenses per ha are estimated at $300 for plants, $150 weedicides, $750 pesticides, $100 power, $100 water, $160 fertiliser, $3000 labour, $1650 machinery hire, $250 fuel, $7500 harvesting costs and $3000 pruning. First grade blooms will return $0.25 per stem, second grade $0.10 and third grade $0.05. Overall annual expenses are of the order of $16,960 per ha, against income of $19,800, with a gross margin of $2,840 per ha.

Key contacts

Margaret Sedgley
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

Geoff Sullivan Ausbud
Redlands, MS599
Jandowae, Qld 4410
Phone: 076 686 118
Fax: 076 686 191 FECA

(Flower Export Council of Australia)
P.O. Box 137
Nedlands, WA 6009
Phone: (09) 327 5563
Fax: (09) 327 5683

Michelle Wirthensohn
Department of Horticulture,
Viticulture and Oenology
University of Adelaide
Waite Campus
Glen Osmond, SA 5064
Phone: (08) 8303 7224
Fax: (08) 8303 7116

Beverly Karpinski AF&PGA
(Australian Flora and Protea Growers Association)
Spring Valley Frogmore, NSW 2586
Phone: (02) 6385 6222

Key references

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 1995–2000.

McComb, J.A., Hardy, G.E. St J. and Dell, B. 1996. Eucalyptus. In: Horticulture of Australian Native Plants and Their Uses. Eds K. Johnson and M. Burchett, New South Wales University Press. Chapter 12, 153–181.

*About the authors