The wonderful spring weather is continuing with warm sunny days and frosty nights – Plants in the school greenhouse are bursting into a new seasons growth but are needing lots of watering with a drying sun in the day and drying heating at night.
Today’s orchid of the day is our second Gastrochilus species of recent times following Gastrochilus sororius in December (below)
Today’s Gastrochilus calceolus is similar but G. sororius has much more fleshy leaves and G. claceolus has longer, sparser, flower spikes. The attractive flowers of both species are rather similar and always make me smile – a good comedy orchid genus, especially as the name refers to the belly like lip.
Gastrochilus calceolus is the type species for the genus and we have seen the species flowering in Sikkim at Tinkitam where is grows amongst Cymbidium devonianum and Coelogyne cristata as an epiphyte in large mossy trees at 2000m. It is actually found across a really wide range from the Himalayas through South East Asia, the Philippines and Borneo, and from 230m in warm forests to 2300m and cool forest. We grow our plant in our warm Asia section where it seems very happy in shade and watered all year, but in a 10cm basket as it seems to resent getting soggy. In fact it is now growing better than ever since the basket was knocked by a student and all the compost fell out!
We have had this lovely small growing species in our collection for 28 years and each year it delivers these lovely clusters of pink flowers that last from February through to early April.
We feel that this is an orchid no one should be without. It is a strong growing little plant that flowers at the ends of short canes each spring and over time it becomes a beautiful mass of roots and stems.
The species is native to Central America where it grows from 1200-1500m in coolish evergreen or semi evergreen forest. We find that it is not fussy about temperature – it grows well in Cool Asia, Cool Americas, Warm Americas and Warm Asia but it does enjoy air to its roots (mounted or in very open bark compost) and plenty of water.
It has the advantage of propagating really easily – either by seed (and we have seedlings flowering just 1 year out of flask) or by division as it produces lots of small plants on its older stems as it grows.
We have done more label changing with this plant that most. In 1993 our plant arrived as Epidendrum centropetalum but it changed to Oerstedella centropetala soon afterwards as Epidendrum was split. A further change to Oerstedella centradenia followed, but from recent molecular studies it has returned to Epidendrum, and is once again Epidendrum centropetala. The plants don’t seem to mind what we call them.
This knock out orchid is stealing the show again in the School Greenhouse. Seeing this orchid flowering reminds me of our wonderful trips to Africa where this species is appropriately known as the Leopard Orchid.
Ansellia africana, the Leopard Orchid, is found right across tropical Africa from South Africa in the South, where we have seen plants growing in coastal forest near Durban, to Uganda in the North.
The forest we found it in in South Africa was open and experienced a seasonal dry season in the winter giving a clue to the correct cultivation of the species which is to grow it in good light with a wet summer when it is in rapid growth (plenty of feed too) and then a dryer winter rest when it flowers but does not grow. In fact many of it native habitats experience long periods of drought.
We have four large plants now of this clone which we raise from our own seen in the school lab. The seed was sown by students in 2004 and the plant was sold at the Eden Project in-vitro in October 2006. It then spent nine happy years with its owners in Cornwall before outgrowing the available space. It was donated back to Writhlington where it was clearly delighted to be home filling Warm Americas with its lovely spotted flowers during February, March and April and winning a number of awards including a cultural certificate from the RHS.
The plant has been divided and we have kept four large plants. The plants sat without leaves or new growths for four years after dividing showing a natural response to what the plant must have identified as a sustained drought before bursting back into growth.
Plants are huge, with 1m long pseudobulbs that produce 70cm branched spikes and hundreds of flowers. We have never seen a clone as good as this one which was a cross between the dark form of the species and a lighter spotted one.
Orchid seedlings in pots in the school greenhouse
The next few months are the ideal time to de-flask orchid seedlings. The extra spring light and warmth will encourage plants to put out fresh roots and establish before the real heat of the summer. Here is the way that we de-flask seedlings and get them growing in the greenhouse.
The starting place is of course our in-vitro growth room where we have thousands of orchids growing from seed. the plant will have spent at least two years in the growth room before they are ready to de-flask into pots.
We look for seedlings that are a good size (for their species) and have a well established root system so that they will survive the move to pots from their perfect world in a jar.
For example, here are some Cymbidium tracyanum seedlings – ready to be de-flasked with the aid of a bowl of water (+ a couple of drops of washing up liquid but not too much) at 27 degrees Celcius.
We start by swishing some water around in the jar to loosen the agar, and ease the seedlings out without damaging them.
We wash most of the nutrient agar off the seedlings.
…and split the seedlings into clumps while avoiding root damage and disturbing the roots as little as possible.
the seedlings are now ready to pot
We pot seedlings in little clumps into 5.5cm pots in large bark (the same as we use for all our orchids)
The seedlings are labeled and watered as soon as we can to avoid desiccation.
Our seedlings live together until established and plants in a clump can be separated when they are next repotted.
Some seedlings are finer rooted than Cymbidium tracyanum but the process is very similar (Cymbidium wenshanense below)
We find growing orchids from seedlings in-vitro a really rewarding experience, and it is surprising how quickly we find seedlings reaching flowering size. Cymbidium tracyanum takes us around four to six years out of flask, but time flies and todays seedlings are on our third generation of tracyanums at school.
We will be adding a range of species in flask to our shop over the next few months – we always sell flasks of seedling at a stage ready for de-flasking
Some botanists are hopeless in selecting names and beautiful orchids like this small growing Pleurothallis species end up with uninspiring names that don’t do them justice.
Pleurothallis pallida is endemic to Panama where it grows in warm wet forest making it more heat tolerant than some of our smaller pleurothallids.
Attractive sprays of pale pink flowers are produced from the base of leaves and the flowers open together.
The plant shown is in a 5.5 cm pot showing the diminutive stature of this lovely orchid.