Pleiones are quite easy to grow in spite of the fact that they are orchids, and most people assume that they need a lot of heat in the winter. In fact the reverse is true, as they need cold for most of the winter. They are only in active growth in spring and summer.
In the wild they are found growing in moss or soil on steeper slopes or cliff faces in the foothills of the Asian Mountain ranges such as the Himalayas, so they are used to standing some degree of frost. Many people successfully grow them outdoors in the UK, only protecting them from the excessive wet and cold by covering them with a glass sheet or straw for example. They enjoy a well drained compost and suitable ones can be made from various mixtures of the following; Orchid bark / leaf mould / sphagnum moss / perlite. The one we use is 10 parts by volume of medium grade Orchid bark, plus 1 part of coarse perlite, 3 parts of leaf mould, and 2 parts of sphagnum moss. You may also use some charcoal but it is not essential. Pleiones need repotting every year.
The following notes will now describe the typical year in the life of a Pleione.
JANUARYBulbs are still in a dormant state and the first thing to do is to prepare them for repotting.
I prefer to leave the bulbs in their old compost until early January to prevent the premature shrinkage by dehydration so they remain undisturbed and cold. Start by carefully lifting the bulbs from the old compost and shake off the excess. Break up the group of bulbs and bulbils. You will be left with the old roots and the remnants of the previous years shrunken (back) bulbs, both of which have to be removed. Trim back to within ½ inch of the bulb base taking care not to damage the new embryonic growth buds which lie on the underside of the bulb but generally outside the roots. (Usually 2 to 3 new buds are visible). Also remove any surface vegetation. The bulb is now ready for repotting. Using shallow pan type pots, loosely fill to within an inch of the top and plant the bulbs some ¾ of their depth, firming around them. In a standard 140 mm diameter 90 mm deep pot place 5 or 6 bulbs around the edge and 1 in the middle . Alternatively pot them up singly, but a group display is more spectacular. Spray with a little rain water and leave to grow in good light and a gentle heat. Plant up the bulbils (small bulbs) in separate pots or trays.
FEBRUARY / MARCHIn about six weeks you will see flower shoots appearing. Continue to spray with rain water every week or so until the flowers have come and gone. Do not soak the compost with water until the bulbs are in full growth otherwise you will kill the roots and the plants will not recover. From the beginning of March it will be necessary to reduce the light levels by either shading or placing the pots in a shady area to prevent leaf scorching.
APRILPlants are now in full growth and the leaves should be around 4” long and the flower stems will have died back. These can be removed by the hand by gently pulling the old stems out. Continue to water sparingly but increase this amount as the leaves grow, until eventually you can water generously.
MAYStart feeding the plants based on using a balanced fertilizer but apply at ½ strength stated on the label. Feed at alternative watering and continue to feed until the middle of August and then switch to high potash feed until the end of September. During the hot summer months it is better to place the pots outside in a shady position,, for the plants prefer not to be subjected to very high temperatures, they like to be grown in temperates of around 50- 75 F.
JUNE / JULY / AUGUSTKeep pots outside in the shade and continue to water and feed as stated above. During this time the leaves will grow to perhaps 12-15” in length and you should see several new bulbs growing from the old bulbs; on average you should see 2-3 new bulbs from the old bulbs in a full season. Keep an eye out for pest which are few but spray with a weak solution of soap or recommended pesticide such as malathion.. Regular overhead sprays of water will be beneficial on summer evenings in addition to the normal watering.
SEPTEMBERAt the end of September or before the first frost , bring the pots inside a cold greenhouse or cold room. gradually reduce the watering and feeding.
OCTOBERStop watering around the middle of October.
Allow the pots to dry out and protect from frost as a precaution. After a couple of weeks the foliage will start to go brown and die back. Eventually the leaves will either drop or can be removed easily to give bare bulbs.
NOVEMBER / DECEMBERContinue to clear away the dead leaves but other then this do nothing to the bulbs until it is once again time to repot in January.