Dendrobium speciosum is the Botanical name for the Sydney Rock Orchid, and is also known as the King orchid. It is an Australian Native plant, and naturally grows over a very large area of the Continent, from cold areas with frosts in winter to warmer areas with temperatures reaching 45 degrees centigrade. In late Winter and Spring, it puts on a spectacular mass display of fragrant flowers, with the flower sprays up to 30 cm long. The plant has many sub-species, and can be quite variable in flower colour, ranging from white and creamy yellow to Golden.
The plants will grow into large clumps, and is found growing amongst or on top of rocks in the bushland, where it is shaded by a tree canopy, in a brightly lit spot and where the roots can stay cool and get some moisture during the rain. The Sydney Rock orchid is extremely tough and will survive in droughts and it is also virtually free of pests, as the leaves are tough and leathery and not edible. They can also be grown in pots, but they require a very well-drained course orchid compost and a position where they get bright light but not direct hot sun.
I photographed these Dendrobiums in Sydney gardens, where they are in full flower.