We have some summer flowering cymbidium species in flower this week – the first is Cymbidium suarvissimum.

Cymbidium suavissimum is not a common species and has only been found in small areas of northern Myanmar and northern Vietnam where it is found in warmish evergreen forests at about 800-1000m so is a little warmer growing than many of the Himalayan cymbidiums. It is also unusual in being a July/August flowering species. It’s closest cousin is Cymbidium floribundum which has similar flowers but is smaller growing with less flowers and none of the gorgeous scent (citrus and fruity) present in this species.

We have tried growing the species warm and cool and can now feel that the key to flowering the species is to grow decent sized pseudobulbs with plenty of feed and water through the growing season. It seems to resent being cold and damp in the winter but does not seem to like life too hot either, although it coped with this week.

The temperature has finally cooled in Radstock – a relief heat sensitive species including today’s Dracula sodiroi. The species is endemic to cool wet forests in Ecuador from 1500-2400m altitude and, in common with other dracula species, is sensitive to high temperatures if not kept very wet in summer. Heat stress shows at black spots on the leaves, our leaves are spotless despite the week we have just had

Dracula sodiroi has unique flowers that hang like little orange lanterns and are produced in twos or threes, well spaced, on spikes clear of the lush green leaves. The insides of the flowers are covered with white hairs. Flowers are about 2cm across and 4cm from the top to the tip of the tails.

The flowers are long lasting and once a plant is happy it will produce flowers on and off throughout the the summer and autumn making it a very rewarding species to grow.

Our plants have coped with Mondays hot weather – here in Radstock the highest temperature recorded on our weather station was 34.7C and the greenhouse temperatures hit 39C Some of our plants positively enjoy the warm weather and one of them is  Phalaenopsis pulcherrima. This species, long known as Doritis pulcherrima, is unusual in so far as it is a terrestrial species (found on rocks and sandy places) which explains the very upright flower spike and rather upward facing flowers.

Phalaenopsis pulcherrima is found across a very wide range from the Himalayas in Sikkim, right through South East Asia, Borneo and Sumatra. Throughout its range it is restricted to hot lowland forests, often in bright light making the species more tolerant of bright light in cultivation, where the leaves will turn reddish purple. In its Himalayan range the species experiences a long dry season but plants seem to enjoy watering throughout the year in cultivation (or in its Borneo habitats where the dry seasons are short)

The plant here is the coerulea variety with beautiful blue/purple flowers although the more common bright pink variety is also stunning.

The species has been extensively used in breeding where it gives very bright pink flowers, upright stems and a tendency not to re-flower on old flower spikes. With Phalaenopsis pulcherrima you get your flowers all in one go and we can’t wait for the rest of this spike to open.

I have been asked how we are keeping our plants cool in this extreme heat. Our policy is to water plants morning and evening. with lots of water at the roots they can cool down by transpiration. We dont damp down as high humidity in the day reduces plants ability to transpire and just makes for slippery floors. Any particularly vulnerable plants are dropped to floor level where it is coolest.

Back to Prosthechea brassavolae. This wonderful orchid flowers every July and transports me to the mountains of Costa Rica and the 2005 school expedition to the forests of Poas Volcano.

Prosthechea brassavolae is an impressive species, and one of our real favourites, with 40cm bulbs topped with two 50cm leaves, and the 80cm flower spike carries up to 30 large flowers.

We found Prosthechea brassavolae to be the most common large flowered orchid in the Bosque de Paz reserve in central Costa Rica. The habitat is wet evergreen forest at 1400m with lush epiphytic growth of ferns, bromeliads and orchids (our photo of the reserve below) on large evergreen trees. Prosthechea brassavolae grew mainly on the lower branches of the large trees competing with the other epiphytes and holding its flowers clear of the foliage to attract its pollinator.

The species is fragrant at night and probably pollinated by moths. In 2005, two A level science students tried to camp out at night by one of the flowering plants of Prosthechea brassavolae to try and photograph the moth in question. However the rain forest can be a bit spooky at night, and in Costa Rica is full of the sounds of exotic animals so the sixth formers lasted less than an hour before returning to the comfort of a hammock at the lodge. Perhaps we will have another try sometime.