This year our relatively young plant of Dendrobium wardianum has two pseudobulbs covered in wonderful flowers.
Dendrobium wardianum is a pendulous plant with long psuedobulbs up to 100cm long. It comes from the Eastern Himalayas from Assam through to Vietnam where it is found from 1000 to 2000m and so experiences a monsoon climate with a warm wet summer and a cooler dryer winter. It is deciduous and needs a cooler dryer winter rest to lose its leaves from the previous year’s growth and then flower in April from the bare pseudobulb.
The flowers have that delightful dipped in pink ink tip to the petals and sepals as well as a lot of yellow in the lip which distinguishes it from the similar looking Dendrobium nobile. Dendrobium nobile also flowers of pseudobulbs produced two years ago not the most recent ones like this species. Dendrobium nobile and Dendrobium wardianum form the basis of a large group of hybrids.
We grow the plant in our Warm Asia section where it always produces the new growth before flowering so we don’t give a completely dry rest.
Another orchid that starred on our London display was Vanda ampulacea. The plant is now in full flower and reminds us of our visits to Sikkim at this time of year.
The species (which is also known as Ascocentrum ampulaceum) is one of the most dramatic species we have seen flowering during our expeditions to Sikkim and seeing it in flower in the greenhouse transports me back to the those wonderful trips.
Vanda ampuilacea grows abundantly as an epiphyte in hot valleys from 200-500m altitude where it clings to trunks, branches and twigs of deciduous and semi-evergreen trees . Here it has to cope with a dry winter exposed to the sun and it does this by developing a very extensive root system that can store a lot of water. (see plant in site below)
Note the lack of moss on the tree trunk showing the dry conditions experienced at low altitude in the dry season. We grow this species in a basket in open bark compost and keep it in Warm Asia (min 20C) for most of the year apart from a short completely dry rest in the roof of Cool Asia (minimum 10C) during February. Moving the plant back to warm conditions initiates flowering. I am really pleased to see that our plant has the same dark spotting on the tough leaves as this plant in Sikkim suggesting we have the conditions in Writhlington about perfect.
One of the most admired species on our recent London display was Dendrobium thyrsiflorum
This majestic species is native to Eastern Himalayas and South East Asia. We have seen it on school expeditions to Laos growing in the tops of tall trees in evergreen and semi deciduous forest at around 1000m where it experiences warm wet summers and a dryer cooler winter.
To reflect the natural habitat we grow the species in Warm Asia during the summer but move it to cool Americas for the winter which encourages perfect flowering as you can see from the photo of the plant at London.
The species is closely related to Dendrobium densiflorum (day 97) which grows further west in the Himalayas, has shorter differently shaped bulbs and flowers that are all yellow and tighter on the spike.
The second clone we displayed at London has fewer longer spikes and we have seed germinated from the cross between the two clones which will be available in about 18 months.
One of the smaller species on our London display was this miniature Vanda species with a striking purple lip.
Vanda coerulescens is native to dryish monsoon forests in the Western Himalayas (Arunachal Pradesh), Myanmar, Thailand and Southern China from around 300 to 1200m. The habitat we have seen in Arunachal Pradesh is open forest with a distinct wet season in the monsoon summer.
We grow the species high in Warm Asia where it gets plenty of light and dries out quickly between waterings.
This extraordinary orchid is the Violet Birds Nest Orchid – Limodirum abortivum. As a saprophyte it relies on mycorrhizal fungus and has no leaves.