Dendrobium biggibum can be moderately challenging to grow in the southern states of Australia. If you had asked several years ago if we could grow this species or its hybrids to acceptable exhibition level, the answer would have simply been no. However, in recent years we have made some discoveries about how to grow these plants quite well.
Firstly we changed the potting media nursery wide from 70% pine bark, 15% river gravel and 15% coarse perlite to 80% pine bark and 20% 10mm scoria. This media drained faster and this subsequently aided in superior root growth. As a result new growths the following season were visibly more robust. Watering has been dramatically in the cooler months. This not only maintains root quality but probably assists in better flowering also. Previously we had grown these plants in an enclosed hot house, at a constant temperature of 18 degrees Celsius. We invested in a heat mat from our local electrical supplier and covered this with river sand to encourage a high level of consistent humidity throughout all seasons. The thermostat is currently set at 15 degrees Celsius and a small fan runs all year round for constant air movement. The growing area itself is simply covered in horticultural solarweave and has an attachable layer of 70% green shade cloth for the summer months.
This year two Dendrobium bigibbum flowered to award standard; ‘Venus’ AM/AOC-HCC/ANOS 2018 and ‘Liam’ HCC/AOC-ANOS 2018. Both of these plants were bred by Don Cruickshanks and purchased as seedlings. Den. bigibbum‘Venus’ is Den. bigibbum‘Ronander’ x ‘Sunset’ while Den. bigibbum‘Liam’ is Den. bigibbum‘Phil’ x (‘Greta’ x ‘Stella’). These plants are the first ANOS quality awards for the species since 2010. Both plants have quality flowers, however what is most exciting is the quality of culture.
These changes have also had positive impacts on hybrids containing Dendrobium bigibbum as one parent. Two standouts this season were DendrobiumPhena’s Charm ‘Genesis’ (Den. Brinawa Charm ‘Lucky’s Toy’ AM/ANOS 1992 x Den. bigibbum‘Wilko’s Best’) which is 62.5% Den. bigibbum and DendrobiumWarringah ‘Stripes’ (Den. bigibbum‘Wilko’s Best’ x Den. speciosum var. capricornicum‘Pine Mountain’) which is 50% Den. Bigibbum,both bred by the late Brian Gerhard. Both plants displayed improvements in flower size, shape and colour. Unfortunately, these plants were not of award quality as the first mention was slightly bunched on the inflorescence and the later did not last due to such inconsistent temperatures.
We have learnt to grow these plants to a higher standard, the most important point learned is not to be afraid to change plant culture and try something new.
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