Sydney Rock Orchid
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. 
Dendrobium speciosum, or rock lily, is a popular and easy to grow Australain native orchid. It bears showy racemes of cream flowers sometimes with purple spotted throats in spring. It naturally grows as a lithophyte, growing on rocks, or sometimes as an epiphyte, growing on the trunk or branches of trees. It is not well adapted to growing well in normal soil, so should be grown in a position that is similar to the natural conditions. It can be grown in a pot with a good orchid mix and can also be attached to logs.
https://www.gardeningwithangus.com.au/dendrobium-speciosum-rock-lily/
Fav. comment Award ! Thanks for the great Pics.
Australia's favorite Dendrobium, 'Rock Lillies' they call them as they can grow on exposed hillsides in full sun. I have a number of them, will post them here as they open up. This one is a hybrid called 'Golden Arch'. (Lynette Banks x spec Yellow Moon), so I guess it's not really a Dend speciosum but a Dendrobium. I think of it as a Dend speciosum, correct me Arthur.
A Viet Namese grower from Orange County brought about 500 seedling into California some time ago and has them numbered 1 to 10. Don't exactly know how he gets that but whatever. #1, sold by him always looks the same, divisions I guess. The flowers are large but not placed too well, not compact and a little rambling all over the place.
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Silly Sausage Award ! Excellent selection of Pics, thanks.
They can be grown on a rock by sitting them on some orchid compost and propping them up with smaller rocks: they will eventually attach themselves to the main rock. They can also be affixed to a tree using an old stocking partially filled with orchid compost in which to anchor the roots - tie the orchid onto the tree with the ends of the stocking. Eventually it will adhere itself onto the bark. They can also grow in cut-up tree stumps. They can also be wired onto boards. If grown in pots, they need very well-drained orchid medium. They should not be planted directly into soil. Give them water, especially in summer, and some liquid fertiliser occasionally in spring and summer. They need sun to promote best flowering. The colour of the flowers can echo cream-coloured Clivia that appear at the same time, and also consorts well with the soft blue flowers of Salvia fallax. Propagate by removing rooted pieces from the clump. The main pest is the dendrobium beetle, which can ruin leaes, new shoots and flowers. Remove them by hand in the early evening. You can flick them into a container with some soapy water at the bottom.
http://www.igarden.com.au/plant-type.jsp?t=Dendrobium
Dendrobium speciosum is one of the world's most underrated and exciting of orchids. They are capable of producing possibly the largest display plants and most spectacular shows of mass blooming of any known orchid. Extraordinarily tough, hardy and drought tolerant it should be one of the most cultivated plants ever! It can tolerate near frost to temperatures over 45°c without severe damage.
This orchid is native to a vast section of Australia ranging from Mallacoota (37°33'S) in South-East Victoria to the tropical conditions up past Cairns (16°57′S). Because it is found over such a vast region, botanists have broken the species apart into many subspecies or varieties. It seems every few years they change names again, so we will mainly use the oldest and most accepted names in this guide.
In almost every occasion I have seen this orchid in the wild, it is growing on granite cliff faces or boulders in open grassy paddocks. The photo below shows just how open bright and exposed these magnificent orchids require. They are huge growers, so in time they may require a giant tub or preferment position in the garden.
Source: https://www.australianorchids.com.au/pages/dendrobium-speciosum-the-sydney-rock-orchid
Once in a past life when I was a beginning native dendrobium hybridist emeritus AOC judge Gordon Giles said something to the effect that "the trouble with you native breeders is that you muck around in your backyards with your toothpicks and you still haven't come up with a hybrid that is as good as a decent speciosum". Although this observation rankled a bit at the time I think I know what he was getting at. 'Rock Lilies' can reliably produce long racemes of relatively large white, cream or yellow flowers late in winter or spring and, being native to most of the Australian east coast, will thrive in their home range given minimum care. Dendrobium speciosum Var. speciosum 'National White' HCC/OSNSW is definitely my favourite native and possibly my favourite orchid overall even though there are probably 'better' clones around.
Den. speciosum does best when given a little protection from the weather extremes of the increasingly angry summer sun and biting winter frosts but even then they will survive these tortures looking only a little worse for wear as a result. There is no need to molly coddle these workhorses like some of the newer temperature and water sensitive hybrids! The ideal situation would be where they receive sun from dawn to sundown under 50% shadecloth on benches that enable some degree of control over slugs and snails.
https://www.ssos.org.au/GrowingDendrobiumSpeciosum.htm
Thanks again for sharing some great photos and bringing great content to the #Steem Blockchain.
It is always my pleasure to share your content on twitter for my followers to see and promoting #Steemit at the same time.
Have a great week.
Stephen
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Dendrobium speciosum, commonly known as the Sydney rock orchid or rock lily, is a highly variable Australian native orchid that forms a species complex. Its varieties can be found in a range of habitats as an epiphyte (on branches or trunks of trees) or a lithophyte. It has a continuous distribution along the east coast of Australia and in distinct populations along the Tropic of Capricorn. As a lithophyte, it forms gigantic spreading colonies on rocks and cliff faces, often exposed to full sun, with its roots forming dense, matted beds across the rock that anchor the plant. It can be found at altitudes from sea level to 900 metres (3,000 ft).
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There are two to five thick, leathery leaves originating from the top of each pseudobulb. These leaves can remain on the plant for up to 12 years. The erect or curved pseudobulbs are large, up to 45 cm (18 in) long. They are thickest at their base, measuring 5 to 7 cm (2.0 to 2.8 in), and taper towards the apex (3 cm (1.2 in)). The showy flowers grow in long racemes on straight or slowly arching, long, starchy stems. Some varieties produce 100 or more 2 to 5 cm (0.8 to 2.0 in), sweetly fragrant flowers per raceme in winter or spring. Flower colour, depending on variety, can be white, cream, yellow or dark yellow. Some cultivars have golden hued flowers. The (predominantly) white labellum is covered with purple dots and veined with red and purple.
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Dendrobium is a large genus with around 1400 species spread throughout Asia and the Pacific. Australia has about 56 species, many of which are cultivated. Considerable hybridization has been carried out within the genus to produce improved horticultural forms and a number of naturally occurring hybrids are also in cultivation.
Major taxonomic revision of the Dendrobium group has occurred in recent years with many species being transferred to new genera. Some of these changes have been reasonably widely accepted (eg Dockrillia) while the status of others is less certain. The various forms of Dendrobium speciosum have been transferred to the genus Thelychiton by some authorities but the earlier name is retained here until the taxonomic situation becomes more clear.
Dendrobium speciosum is a lithophyte (growing on rocks) or an epiphyte (growing on another living plant, but not parasitic in nature). Pseudobulbs are up to 45 cm long, erect or spreading, thickest near base and often tapering towards the apex. There are usually 2 to 5 thick leaves at the top of each pseudobulb. Flowers occur on long stems in large clusters which may consist of over 100 flowers per stem. They are usually pure white to creamy yellow with purple dots on the labellum. Flowers are seen from late winter to spring.
There are a number of different form and varieties of Dendrobium speciosum which will become new species under the taxonomic revision. The most commonly encountered are D.speciosum var.speciosum and D.speciosum var.hillii. The later is now regarded as Dendrobium tarberi by many authorities and differs from D.speciosum var.speciosum in having longer, untapered pseudobulbs and is more commonly found growing on trees.
D.speciosum is popular in cultivation and is easy to grow in tropical to temperate climates. It can be grown on branches of trees or on rocks where it receives nutrients through the break down of leaf litter that accumulates around its root system. While the plant is establishing its root system, it may need to be fixed into position by wire or twine. Eventually new roots will form which will grip the substrate firmly. The plant should not be planted directly into soil as the root system is not adapted to constant moisture.
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