Irrigation
Verticordias should be planted into moist soil and the surface kept moist during establishment using drippers, particularly on sandy soils. In summer, on sands, this may require water to be split into three applications per day. During summer V. plumosa plants grow better under drippers rather than micro-sprays.
Drippers give deeper water penetration than micro-sprayers which aids plant growth. Verticordia species can be over-watered causing loss of plants and it is advisable to apply water based on tensiometer readings. Typical evaporation replacement rates are 50-80% depending on species.
Pruning
Verticordia should be pruned in the first year of growth to develop a good branch structure. They have a tendency to develop bare wood after two to three years if left unpruned. New shoots do not develop from bare wood and pruning back to bare wood will most likely kill the plant. New plantings should be lightly pruned after the first year to develop a branch structure.
On established bushes, stems should be pruned back leaving 10-20cm of the current year’s growth. The best time to prune is during harvesting of flower stems, with some cleaning up following harvest. If they are summer flowering and conditions are hot it is better to leave any unpruned branches after harvest until conditions become cooler in the autumn.
Pest and diseases
Verticordia are susceptible to fungal diseases such as powdery mildew and alternaria. Those most at risk are fine-leaf rather than round leaf species. For species at risk preventative sprays are required starting monthly in summer and increasing to 10-14 day frequency in autumn and over winter. Fungicides used should be rotated to prevent resistance developing.
Postharvest handling
Generally Verticordia species have an adequate vase life of 10 to 18 days. A number of species flower during late spring to summer when field conditions can be quite hot (30-40ºC). To maximise vase life it is necessary to ensure picking is done in the early morning and that stems ends are stood in buckets of clean water and moved quickly from the field to the packing shed. Stems should be cooled (1ºC) as soon as possible to remove field heat.
No special vase solutions are required for Verticordia species. Many are insensitive to ethylene and do not require silver thiosulphate or similar ethylene protection. Tests by DAFWA have found that V. nitens, V. cooloomia, V. grandis and V. serrata are sensitive to ethylene and should be treated accordingly.
Verticordias pack well and can be bunched and boxed similar to waxflower. For finer-stemmed species such as V. luteola rosea stem numbers may need to be 10–15 per bunch to make up to the required 400 gram bunch weight.
Flowers tend to attract insects, particularly thrips, and should be sprayed in the field then postharvest treated by dipping or with Insectigas®/Pestigas® aerosol treatment before export.
Marketing
Being able to supply different colours (yellows and reds) means that Verticordia species have a real market advantage. To capture that advantage, stems need to be of the highest quality to develop a market niche for these flowers.
Acknowledgements
The support of the Australian wildflower industry is gratefully acknowledged.