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Cultivation of Pleiones |
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Cultivation of Pleiones |
Below I describe how to grow Pleiones. This general advice covers all the hybrids and many of the species. At the end is a section titled "Exceptions" discussing the requirements of those that need differing treatment. This page is all text for now but eventually I will add some pictures to illustrate various points.
If I have missed anything out, or if you have a specific question you would like to ask, please feel free to contact me and I will do my best to help you.
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Pleiones come from areas with distinct seasons of Spring, Summer, Autumn and Winter and grow best wherever the average summer temperatures dos not exceed 25 centigrade (though a few odd days up to 30 centigrade is tolerated). In winter, while they are dormant, they need to be kept cold but just frost-free. A range between 1 and 5 centigrade is ideal. If need be, small numbers can be kept in a fridge if your winters are usually too warm. Within these restraints they may be grown on a windowsill, in a glasshouse or coldframe and may be outside for those months that are frost-free. In areas with few and gentle frosts they can even be planted in the garden. But most people grow them as pot plants.
Clay or plastic pots can be used and both have their devotees. Clays may need watering more frequently but the evaporation from their surface helps to keep the roots cool and provides humidity around the plants. Plastics need less frequent watering, are easier to clean and lighter to use. Many growers use half pots, pans or seed trays, as Pleiones are shallow rooting in the wild, while a few use deeper pots. Kew says they find that they are not especially shallow rooting and suggests they will adapt themselves to whatever depth of container is provided, so long as the compost structure and watering are correct. It is probably wise to thoroughly clean and disinfect pots before use.
Pleiones can be potted or re-potted anytime while they are dormant. I usually do mine in late January/early February. Any old compost should be cleaned off and the old roots trimmed back. Some trim them very short - to 1cm or so- while others prefer to leave them rather longer to help anchor the pseudobulb in the new compost. The pseudobulbs should be planted with approximately one third their depth sticking out above the compost and spaced about 2cm apart. A few seem to prefer being completely buried (P. bulbocodioides, yunnanensis, limprichtii and scopulorum). They will grow in a variety of compost mixes, the main requisites being that the mix should be very "open" and free draining. I have used two different mixes: (All "parts" are by volume):
2 parts bark and 1 part moss. The moss may be wood moss or sphagnum. The bark can be medium grade orchid bark or even a good quality mulching bark. Here in the UK I have used a product called Melcourt Potting Bark, which is similar to (though not quite as good as) orchid bark in quality. I used to use this for all my hybrids.
2 parts fine grade orchid bark, 3 parts sphagnum moss, one part perlite. This mix holds more water and I find that the species and hybrids do better in this mix for me. I now use this mix for everything.
Many other mixes are suitable - you can use pure wood moss or pure sphagnum, or a mix containing these along with such ingredients as bark, pine needles, leafmould, coarse peat, perlite and others - the main aim is to get a "scrunchy" or spongy, open and free-draining mix. There are as many recipes as there are growers!
The critical time is early in the season. The roots usually start to grow more or less as the flowers fade and at this time it is important to give only a little water - the aim is to keep the compost only-just damp and make the newly-emerging roots go searching for moisture. If the mix is too wet at this time there is a danger the new roots will rot. Once however the roots are well established (often evidenced by rapid leaf growth) watering can be increased substantially. Pleiones come from areas which get the summer monsoon. As long as your mix is very free draining, it is difficult to give them too much water once they are actively growing. Rain water, soft tap water or RO (reverse-osmosis) are best. If you have very hard tap water, this is OK but I would be cautious about keeping them too wet. If possible, keep them open to the weather in summer so they can be rained on. They love it! Personally I take the roof glass out of the glasshouse they are in so the rain can fall in on them. It also keeps them cooler. As days shorten in the autumn, growth slows and finally stops and the leaves start to go yellow. This is the time to reduce watering and as the leaf colour starts to go brown, stop watering altogether and allow them to completely dry out. The leaves will finally fall off and the pseudobulbs enter their dormant phase.
Pleiones need to be fed to build up the pseudobulbs for flowering the following year. They like regular but weak feeds with a liquid fertiliser. The old adage of "weakly weekly" comes to mind. Feeding should start once the leaves start to grow quickly. Personally I feed once a week with fertiliser at one-third of the recommended strength. Many people use a balanced one (NPK 1:1:1) to start and change over to a high potash one (NPK 1:1:2) in mid-summer, though either can be used throughout if desired. Personally I start with just a few feeds with a higher nitrogen one (NPK 2:1:1) to get good leaf growth before switching to the usual regime already described. I use the Chempak brand.
When grown under glass, Pleiones need to be shaded from direct, bright sunshine. A shade cloth giving about 50% shade is ideal, or the glass can be painted with a traditional style whitewash. Outside they can tolerate full sun but it is more usual to provide somewhere semi-shaded, for example in the shade of a tree providing dappled light. They also enjoy fresh air, so provide plenty of ventilation. If outside you may also need to think about some protection from birds and other wildlife (not to mention the footballs coming over the fence from the neighbours sporty kids!). Growing inside a fruit cage would be ideal.
Some species require different treatment to that outlined above:
Pleione maculata, Pleione praecox and their hybrid P. x lagenaria are autumn flowering. They have a rather shorter rest period and need to be kept warmer during this time - I suggest a minimum of 10 centigrade. They will start to grow new leaves very early - often before the end of the year - and new roots too. Despite this new growth, do not be tempted to give a lot of water - keep them dry but mist them occasionally and perhaps stand the pot in a few millimetres of water for a few minutes to give some moisture at the bottom of the pot for the new roots to go heading for. Don't start regular watering until you are sure the new roots are well down the pot. P. maculata in particular also likes to be kept warmer in the summer with plenty of humidity too.
Pleione saxicola is another autumn flowerer recently introduced to cultivation, but I don't feel we have enough experience of it yet to best advise on its treatment. It seems to grow a lot of new root very early in the autumn, before even the flowers die down. I am uncertain as to whether it is better to keep it moist so these roots don't die if dried, or to let it dry out as normal. I am also uncertain as to the best temperature for its dormancy. I am experimenting with these factors. Watch this space!
Pleione coronaria, P. hookeriana and P. scopulorum all have a longer, cold winter and a shorter growing season than other species. These species do better if kept cold for longer in the winter, using a fridge if necessary. I suggest keeping P. coronaria and P. scopulorum in the fridge until around early March and P. hookeriana until late March. Keep an eye on them though and take them out if they threaten to flower earlier than this. Also, P. scopulorum unlike other Pleiones must not be allowed to dry out completely during dormancy or it will shrivel and die.
Pleione forrestii also I believe benefits from a long, cold dormancy and should be kept cold until early March if possible. However, this one more than the others has a tendency to flower early and if the buds are clearly developing quickly, remove it from the fridge. It might be worth noting that while cold may delay flowering it will not necessarily prevent it altogether - plants can achieve full flower in the fridge in the dark!
Finally it must be said that some of the species, particularly all those mentioned above, are not easy to grow and we still have much to learn. If any of you out there grow any of those mentioned really well, do let me know how you do it!!