Pleiones have pseudobulbs of about an inch in diameter, more or less. The flowers develop from the base and the buds appear at the side of the pseudobulb. When flowering is over, the leaves develop, and they can be quite large, more than 6 inches long and 2 inches wide. These leaves feed the new bulb which develops during the growing season. When this is over, the leaves drop and it is time to give the plants a rest. At that time, the plants should have developed a new, fat and plump bulb ready for next year. The old shrivelled bulb should be removed, as it could cause problems by rotting, and the bulbs are either left in dry compost to over-winter or removed from their compost. In that case, the roots are trimmed to about 1/2 inch, the bulbs are cleaned and placed in a cool and frost free, dark, airy place until the new buds appear. Then they are potted and the cycle begins again.
In conclusion, Pleiones are very rewarding little orchids, they flower reliably once they reach flowering size, and many bulbs will produce two or even three flowers per bulb. They multiply easily and only take a couple of years to reach flowering size. Some even have a delicious scent.
By choosing a number of different varieties, it is possible to have flowering pleiones for seven months of the year. Certainly worth a try !
During the summer, all will
benefit from a spell outdoors. When you put them out into the garden after
flowering and there is no danger of frost, give them a little shade at first
until they become acclimatised, then they can withstand a sunny aspect quite
well as long as their feet are cool. If they are exposed to the full blast of
the midday sun, a little shading can be beneficial.
After the dry rest period, re-start watering when the first buds show. At this stage the plant have few roots, so water sparingly at first, increasing as growth gets under way. When the leaves develop, usually at the end of flowering, water every week or when the compost has become dry. Lift the pot to test its weight, if heavy, it’s wet; if light, it’s dry. Use clean, fresh water - rainwater if you have it.
hot weather, pleiones enjoy an evening misting over the leaves. This raises
the humidity, which is especially appreciated if they are grown in a
greenhouse. Outdoors, humidity in the air rises in the evenings as
temperatures drop, so the plants tend to look after themselves.
From October, reduce watering and when all the leaves have fallen, remove them and stop watering altogether. The bulbs must have a rest and be completely dry (see detailed explanations lower down).
foliar feed with Maxicrop is also appreciated. Use it at half recommended
During late August / September, change to a higher potash feed, again at 1/4 strength. This will encourage the new bulbs to ripen in readiness for the rest period. Feeding should cease by October and no more should be given until the following spring, when the leaves are growing (about March). Then normal feeding can resume.
Re-pot your pleiones when dormant; just after Christmas would be a good time. Please be careful when handling the pseudobulbs at this stage. If you damage the tiny flower shoot of the spring flowering kind, there won't be another one until the year after.
Question: Why should pleiones be re-potted when dormant ?
Let me explain. When a living pleione root is damaged, it will not dry and form a little stump at the point of damage like any other plant. Instead, the entire root will die right back to the bulb. A pleione has few roots, and losing one would severely set it back. Therefore it is best to wait until dormancy when the roots have died naturally and no harm will come to the plant when roots are cut back.
We recommend leaving about 1/2 inch of dead
root to serve as anchorage when the bulbs are re-potted.
Pots and Containers
For groups of pleiones I use bowls, their diameters ranging from 15cm (will take 5 - 7 bulbs) to 30cm (up to 30 bulbs at a squeeze). Bulb bowls and cactus bowls are very presentable and they have holes in the bottom for drainage. I tend to use clear plastic mixing bowls (less expensive) with great success. They are just deep enough to give the plants a good root run. Holes must be drilled in the bottom to allow water to drain away. The clear plastic allows me to check on root development and the soundness of the compost. When I want to display a bowl, I just pop it into a pretty basket for the occasion.
Tip: Use pots that have two tier or side drainage. Bowls that have holes just in the bottom should be stood on gravel, pebbles, Hortag or similar so that water can drain away easily. Never allow pleiones to get water-logged, for the roots will rot and the plant will perish.
There are many ways one can prevent pots from overheating. I place my potted pleiones into a plunge during the growing season. This is simply a larger container with holes in the bottom and sides, or a raised bed, filled with the same compost, where the pots are submerged with just the rims sticking out. I find that during hot summers, a plunge ensures better and more even retention of moisture and a comfortable, cool temperature in the pots.
A) My current favourite mix (organic) is this, both components to be moist (not wet) before mixing, otherwise the sphagnum stays at the top and the bark falls to the bottom.
B) My previous favourite was the largely inorganic compost below, but my latest growing experience shows that compost A) results in stronger growth. However compost B) is very suitable for most hardy orchids.
Or you could try equal parts of loam, sphagnum moss and medium grade orchid compost, but be careful not to over-water.
Notes on Compost preparation
Notes on over-wintering: it is essential that the bulbs are kept dry during this period. Just to be clear what is meant by 'dry':
Therefore, if you grow your pleiones in a cold frame and you wish to leave them in their compost over winter, leave the lights on to keep out the rain, but leave them slightly open to allow air circulation.
When it gets really cold, you can close them for short periods and place some layers of newspapers, bubble wrap etc. over the plants to protect them from frost. Remember, your aim is to keep them above freezing, but they can survive a short cold spell if kept dry. Depending on your locality, a cold frame may not be an option, a frost-free greenhouse or similar place may be safer.
If taken out of the compost for over-wintering, trim the roots to about 1.5cm (1/2 inch) to aid stability when planted next spring. It is a good idea to soak the bulbs briefly in a solution of Spraying Oil to protect them from the false spider mite Brevipalpus oncidii. Suitable oils can be obtained from Orchid Nurseries or Hydroponics Suppliers.
Store the bulbs in a box in a cool but frost free place. Check them occasionally to ensure they are not rotting. A good way to avoid this is to spray them with a fungicide. Cover the bulbs with a loose sheet of paper to keep them airy but retain some moisture.
Re-planting should commence when the new buds show as tiny shoots on the sides of bulbs, usually about February/March.
All of these should be potted up together in trays or community pots (not singly or they will feel very lonely). As we say, the big ones look after the little ones, meaning that if there is any uneven watering, the stronger, more developed plants will mop up the water and therefore the smaller ones with the less developed root systems will not suffer.
This is the compost I use for small, non-flowering bulbs and bulbils:
Bulbils should be flowering size by the third of fourth year after planting. Make sure you label them - it's so easy to forget...
Last Updated: 19/12/2016 09:47