By Sandra Simpson
The six species of Thunia orchids are native to the lower mountains (600-1000m) of India and Sri Lanka, through Myanmar (Burma) to China, Thailand and Malaysia. Most are terrestrial, some are semi-epiphytic – but all are deciduous in autumn.
The flowers come on new growths, which start in spring from the base of the old, bare canes. These growths rapidly gain size so it’s important to make sure the plant is well watered (but keep water out of the new shoots as they can rot), well fed (more on this in a minute) and slugs and snails are kept at bay. I grow my Thunia veitchiana in potting mix.
The information I got with my plant in 2015 (a TOS raffle win!) suggests a complicated regime of liquid fertiliser once new growths show, the strength of which needs to be gradually built up from one-sixteenth to one-half. Deciding I didn’t have the time for that palaver, the next sentence was perfect. “Alternatively, apply a 6-month slow-release fertiliser at half the manufacturer’s recommended rate.”
I happened to mention a disappointing flowering in 2018 to a more experienced grower and was asked where I kept the plant. “In the shadehouse” (thinking I would protect the new growths and flower buds). “Put it outside from Labour Weekend,” was the reply, advice which I’ve followed – and which has resulted in a flush of beautiful flowers in January, 2019. (Make sure you keep up the snail bait.) Mine now grows against the shadehouse wall where it gets early morning sun and thereafter dappled light/shade, and good air movement.
Although it looks as though each cane is carrying only one bud, these ‘buds’ split into anything from two to five flowers flowers as they open.
Some of last year’s canes, which I’ve tied to a stake in the pot, are throwing kiekies at their tips. Hopefully, the baby plants will be large enough to pot up before these old canes start to wither (after flowering).
Keep up watering and feeding even as these old canes die off because the flowering canes need to be plump by the end of autumn. When the weather cools stop feeding and gradually reduce watering – watering ends when the leaves start to drop. Keep the plant dry and frost-free over winter and then watch for those new little growths coming away again!
Repot into fresh mix when the new growths have a few inches on them.
I have read this online, but not tried it (yet): “Plants can be easily propagated in spring by cutting the previous year’s stems into lengths of about 15cm. Then insert them firmly into pots.”
The genus was first described in 1852 by Heinrich Gustav Reichenbach (1823-90, the world’s leading authority on orchids after the death of his friend John Lindley in 1865). Professor Reichenbach named the genus Thunia in honour of the Austrian statesman (and orchid fancier) Count Leopold von Thun Hohenstein of Bohemia [the Czech Republic].
Thunia veitchiana was first raised by George Toll of Manchester in England, a cross between Thunia marshalliana and Thunia bensoniae, with John Seden, a hybridiser employed by the famous Veitch Nurseries, producing the same plant slightly later.
Both Messers Toll and Seden exhibited flowering plants at a Royal Botanic Society show in 1885, according to J H Veitch in his history of the famous Veitch Nurseries, Hortus Vetichii (1906) – with the name accorded to Mr Seden as he had been the first to supply the information to Professor Reichenbach. Mr Toll had called his plant Thunia wrigleyana.
Thunia marshalliana is named for a 19th century British orchid enthusiast (and that’s all I could find!). Thunia bensoniae is named for Mrs Benson, wife of a 19th century Colonel and British Resident in Rangoon (Burma). Both wife and husband were orchid enthusiasts and have orchids named for them.
Editor’s note: Do you have a summer-flowering plant that’s never seen at a show? Let me know and we’ll organise a website posting.