Cool House and Warm House Orchids

Cymbidium

The only drawback with these winter flowering orchids is their size. They are a graceful plant even when not in flower but if your aim is to grow the largest number of orchids as possible you will not fit many of these into an average sized greenhouse. Do not be tempted to pack them in otherwise their health will suffer.

Cymbidium are naturally epiphytic and the species originate from the foothills of the Himalayas down to Burma. Many people have trouble getting them to flower. Providing they are healthy and in good light this is most probably due to temperature. A night temperature of 10°C (50°F) is ideal with a rise of 4-5°C (8-10°F) during the day. If it is not possible to maintain that rise during the day then the best policy is to drop the night temperature accordingly. These orchids flower better if they are given space and plenty of ventilation when temperatures allow. I stand mine outside the greenhouse in a semi shaded place in summer. Keep the plants drier in August and September which encourages flower spike development. As soon as spikes have formed they can be given more water. Potting, if needed, should be done after flowering although they will flower better if undisturbed. Whilst potting plants they can be divided. Each pseudobulb or swelling with leaves growing from it should have two or three green leafless ‘backbulbs’ attached to it.

Masdevallia

These epiphytic orchids come from Central and Southern America. I really like them but they are possibly not as showy as some other orchids as it is their sepals which provide the attraction rather than the petals. They do not have pseudobulbs and, as such, should not be allowed to dry out too much between waterings. M. kimballiana is an attractive burnt orange.

Bletilla

B. striata is a terrestrial orchid almost hardy enough to be grown outside but is well worth planting in a pot. A compost of equal parts of loam, peat, grit, leaf mould and sphagnum moss is more suitable than bark. Pink flowers appear in May. The plants will go dormant during winter but should not be dried right out.

Warm House Orchids

Odontoglossum

Naturally, these plants grow at high altitudes and although modern hybrids are more adapted to doing well in ‘captivity’ as it were, it still pays to keep a good circulation of air and give ample shading in summer to keep temperatures down. These are epiphytic orchids which bear quite spectacular flowers often from very small plants which gives the collector the chance to accommodate a good selection.

Paphiopedilum

These are sometimes still referred to as Cypripedium. I dislike intensely the huge hybrid flowers which seem fat and bloated to me. I much prefer the species and daintier hybrids and find straightforward P. insigne which must be the commonest of the lot very attractive. P. hirsutissimutn is a very distinct species from Assam with twisted spotted purply petals and dark hairs all over the flowers and stems. P. bracteatum has a delicate shape. These are terrestrial orchids and can be divided culturally into green leaved types which are cooler growing and mottled leaved types which need a warmer more moist atmosphere. The former will grow and flower happily with a minimum temperature of 13°C (55°F) but the latter prefer a minimum of 15°C (60°F). Shading for both must be closely attended to. Keeping moisture away from the centre of the plants, where they may easily rot, is essential.

Dendrobium

These are one of my favourite groups of orchid. They are epiphytes which grow naturally from India down through eastern Asiatic countries to Australia. It is important when growing them to know whether you are dealing with an evergreen or deciduous type. Evergreens hang on to their thicker tougher leaves for several years whereas the deciduous will lose theirs every year in the dry period before flowering. Watch the growth of these deciduous ones carefully as during autumn they will produce a pair of terminal leaves with no little shoot in between. This is their signal that they are ready to rest. Give only enough water every month or so to prevent absolute shrivelling until the flower buds appear. If too much water is given during this resting period they will not produce many flowers but small plantlets instead which can be taken off and grown on separately.

23. July 2013 by admin
Categories: Tips and Advice | Comments Off on Cool House and Warm House Orchids

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