Species and varieties
The most popular kangaroo paws are hybrids of Anigozanthos flavidus with A. pulcherrimus or A. rufus, plus Macropidia fuliginosa (the black and green kangaroo paw). Small amounts of A. pulcherrimus and A. manglesii are also grown.
There is little or no requirement for other species at present. Enquire about market demands before making any substantial plantings as trends in the cut flower industry are cyclic.
Many other kangaroo paw varieties are available such as the Bush Gems Landscapers series, and growers should contact a range of information sources such as exporters, nurserymen, grower associations and the Department of Agriculture and Food, Western Australia, for advice on the best selections to grow.
Soils
Most kangaroo paws prefer well drained, acid sands or sandy loams. None will tolerate wet conditions. M. fuliginosa is especially susceptible to root rots and is also sensitive to phosphorus.
Eastern Australian studies suggest A. pulcherrimus may also be sensitive to phosphorus. If the soil has a history of cultivation, test for soil phosphorus level before planting either of these species.
Climate
A wide range of conditions is tolerated. Frosts from mid-winter to spring will affect flower quality and may render the crop unmarketable. In conditions of high humidity, ink spot and rust may cause problems, although most hybrids have good resistance to these diseases.
Field planting
Plantlets for commercial cultivation are grown from tissue culture and supplied from laboratories in eastern Australia.
Soil preparation may include the incorporation of a base dressing of compost. A base dressing of 500 kilograms per hectare of superphosphate (if the soil is lacking in phosphorus as indicated by soil test results) may be used for all species except M. fuliginosa. This species is sensitive to phosphorus, so do not apply a base dressing. Use half this amount for A. pulcherrimus.
Trace elements should be included in the base dressing at recommended rates.
Although plants may be established at any time of the year, it is best to plant during the cooler months. Kangaroo paws tend to flower about six months after planting but in the following season they flower at the normal time.
In the past, growers have used a spacing of between 80cm and 1m between plants within a row, in beds with four to five rows, each 1m apart with a 3m gap between beds for tractor access. This equates to 6000 to 8000 plants per hectare.
Other plantings have used much closer spacings, sometimes with only 20cm between plants. This can be a problem with less upright varieties as the stems will tangle, making picking difficult. The optimum plant density for flower production has not been determined.
Irrigation
Plants are watered using trickle irrigation. Irrigated kangaroo paws continue to grow throughout the summer. Although the effect of water quality has not been determined, total soluble salt levels less than 800 parts per million (50 grains or 145mS/m) are advisable.
Exact water requirements for kangaroo paws are unknown. Department of Agriculture and Food, Western Australia recommends watering rates according to Table 1. Due to the higher rainfall on the south coast, irrigation from June to September is only needed to supply nutrients.
| Area | October to November | December to March | April to May | June to September |
|---|---|---|---|---|
| Northampton to Coorow | 1 to 2 | 2 to 4 | 2 | 1 to 2 |
| Muchea to Bunbury | 1 to 2 | 2 to 4 | 2 | 1 to 2 |
| South Coast | 1 to 2 | 2 to 4 | 1 to 2 | For nutrient supply only |
Alternatively, if growing in a loam or sandy loam, water to a tensiometer reading of 30 centibars at a depth of about 30cm.
Fertiliser
Supplying nutrients through the irrigation is the most satisfactory method of fertilising kangaroo paws. The recommended fertiliser rates are outlined in Table 2.
| Nutrient | Rate (kg/ha/year) |
|---|---|
| Nitrogen | 100 |
| Phosphorus | 15 (nil for Macropidia) |
| Potassium | 80 |
| Calcium | 20 |
| Magnesium | 10 |
| Trace elements | Use a mixed trace element formulation at recommended rates |
Nutrient deficiency and toxicity
Plants deficient in nitrogen become pale green and few fans are produced.
Phosphorus deficiency symptoms are uncommon. The older leaves develop an orange-yellow colour and die gradually. Phosphorus toxicity symptoms are more common and frequently resemble those of ink disease, that is, a blackening of leaf tips that gradually progresses down the leaf until it dies.
Potassium deficiency symptoms appear on the oldest leaves. The leaf tips die. In severe cases this may be accompanied by brown spots on the outer half of the leaf. There is no yellowing. Plants are poorly anchored due to lack of root development and will often topple over when in flower.
Plants deficient in magnesium develop a blue-black discolouration in the upper half of the older leaves. As the deficiency progresses, plants develop a mass of old dead leaves.
Tissue testing
No standards have been developed for kangaroo paws but the figures (Table 3) for A. pulcherrimus indicate the range that might be expected in healthy plants. The leaves sampled were recently matured.
| Element | Concentration (dry matter basis) |
| Nitrogen | 1.0 to 1.7% |
|---|---|
| Phosphorus | 0.05 to 0.2% |
| Potassium | 1.4 to 2.0% |
| Calcium | 0.3 to 1.0% |
| Magnesium | 0.1 to 0.3% |
| Iron | 60 to 90ppm |
| Manganese | 40 to 150ppm |
| Copper | 2 to 10ppm |
| Zinc | 10 to 50ppm |
A. pulcherrimus appears to accumulate phosphorus. Other species would contain half to one-third of the phosphorus found in A. pulcherrimus (M. fuliginosa is likely to be similar).
Work in eastern Australia showed zinc levels in A. pulcherrimus to be three to four times higher than in the other species and copper levels to be about double but it is not confirmed if this happens in Western Australia.
Weed control
Weeds can be a problem in kangaroo paws, especially in older plants with dead centres. Do not allow broad-leaved weeds to become established since there are no herbicides registered to control them. Post-emergent control of grasses can be achieved with a registered grass selective herbicide. See the Australian Pesticide and Veterinary Medicines Authority (APVMA) website for the latest information prior to use.
For weed control between rows, glyphosate or Sprayseed® may be used with a hood to protect the kangaroo paws. Pre-emergent herbicides such as chlorthal-dimethyl are safe to use over the plants but must be applied evenly and watered in for effective weed control. Application through trickle irrigation is not sufficient.
General maintenance
Some species of kangaroo paw, especially those susceptible to ink disease, respond well to slashing and/or burning in late summer to autumn. Remember to pull up the irrigation lines before burning. The slashing and burning reduces the fungal inoculum load and gives the plant a clean start for the following year.
Pest and disease control
The most troublesome disease of kangaroo paws is ink disease, believed to be caused by the fungus Alternaria alternata. A. flavidus and A. flavidus hybrids are usually least susceptible. A. manglesii is often badly affected and a 1.5m spacing to improve air circulation around the plants is recommended.
A registered fungicide should be used regularly to assist control of ink disease. If certain plants appear to be highly susceptible, it is often better to rogue them out, as they provide an inoculum source for the rest of the crop.
Rust can affect the foliage of kangaroo paws. It may be controlled with a registered fungicide.
Kangaroo paws can succumb to a range of crown and root rots, especially when stressed by poorly drained soil, salt build-up or phosphorus toxicity. Phytophthora and Pythium fungus species may be controlled by reducing watering or improving soil drainage and by applying fungicidal drenches.
There are no chemicals registered for the control of Fusarium rots. Fusarium rots are often characterised by a pinkish colouration to the roots but for positive identification a pathological test is essential.
During spring and autumn, kangaroo paws may become infested with aphids, that cause particular damage during the early flowering period. Control may be achieved with sprays of a systemic insecticide. Leaf miner may be troublesome during winter. Control when the larvae are active. Slugs and snails can be a problem, especially on young plants.
Chemical registrations and permits change frequently so check the Australian Pesticide and Veterinary Medicines Authority (APVMA) website for the latest information prior to use.
Flower production and harvesting
Harvest flowers when the first florets on the spike have opened. Cut the stems at least 20cm above ground level to leave enough base flower stem for possible development of secondary flower spikes. These flowers develop from leaf nodes at the base of the main flowering spike.
Stand the flowers in water and remove from the field as soon after picking as possible.
Flowers should then be pulsed before disinfestation, storage and transportation. This is done by re-cutting stems under water and standing them in a solution of 5 to 20% sugar (depending on species or cultivar) plus a biocide for 12 hours in a lit area at 20°C.
Pulsing with rates of sugar higher than 20% may cause leaf blackening and dehydration of flowers in some cultivars. Test to establish the most suitable sugar concentration for your particular cultivar(s).