How To Grow Pleione
PLEIONE: CULTIVATION & CARE
INTRODUCTION TO PLEIONE
Pleione are a small group of about 25 orchids that originate from the mountainous areas of Northern India, Nepal, Thailand and China. In the wild, these cool and alpine growing species tend to grow in close proximity to the snow line at the edges of forests and woods. They are actually semi epiphytic and not terrestrial as often referred to and grow in the leaf litter that accumulates around the tree bases.
Pleione are the easiest orchids to grow and propagate, with most species flowering in Spring and a few in Autumn. They multiply easily and only take a couple of years to attain their flowering size. Once they reach flowering size, they flower reliably and most bulbs will produce as many as 2 or even 3 flowers each bulb.
The flowers, which usually develop before the leaves, are large, exotic looking and delicately coloured. If you choose well from amongst the different varieties you could actually enjoy the beauty of flowering pleione for as many as 7 months in the year.
LIGHT, AIR AND TEMPERATURE, REQUIREMENTS
Most pleiones are cool growing and will grow well in winter up to a minimum of 3ºC/39ºF with a few of them requiring intermediate temperatures of min 13ºC/55ºF in winter. They don’t do so well when it is cold and wet at the same time with temperatures between 0ºC and 10ºC and they cannot survive at temperatures below 0ºC. Long drawn-out temperatures above 25ºC are not good for them either.
They thrive at normal room temperatures in good light but do not do so well in direct sunlight, which is why they should never be placed on a south facing windowsill. Unheated greenhouses with some amount of shading offer ideal conditions for growing this species. During the frost free months they can even be grown outdoors.
Pleione thrive in bright light and will benefit from a spell outdoors in summer. However, they will need to be protected against the full blast of the midday sun especially from the beginning of March onwards. This is because their leaves are very delicate and tend to get scorched easily. During hot weather the temperature can be reduced by shading, misting or using fans to create air movement.
During the growing season, which is from February to October, the compost should be kept moist by watering every week. Start with very little water in the beginning and only increase when the plants are well established. Stop watering after October to allow the compost to dry out completely. Pleione are deciduous and need to rest through the winter.
POTS & CONTAINERS
Pleione can be grown in pots or other containers made of clay or plastic. Clay tends to dry out quickly but they do stay cooler in the summer months.
Some species prefer deeper pots and others do better when grown in shallow bowls or pans. A pot can ideally accommodate 1-3 bulbs and a 15cm bowl can accommodate about 5-7 bulbs.
When planting singly in a pot, aim for a depth of 11 cm and definitely no less than 9 cm. This allows the roots to grow freely during summer, which helps in the development of good sized replacement bulbs for the following year.
When planting on windowsills, the pots should ideally be placed on trays of gravel or pebbles to facilitate drainage and to prevent the containers from sitting in the drained out water. When pleiones get water logged the root rot sets in and the plant cannot survive.
POTTING MEDIA AND POTTING
The potting medium should provide good drainage yet be able to retain sufficient moisture for the plants to thrive. While these two properties may at first appear conflicting, this can be achieved successfully by creating a fairly coarse medium using a variety of carefully selected components. While the resultant medium is not capable of holding free water between the particles, the particles themselves have the capacity to absorb and hold water.
Ideal Pleione mixes that provide a good combination of moisture retentiveness and good drainage typically contain varying ratios of moss, bark, peat, charcoal, perlite, vermiculite, loam and grit. Most growers use bark as the main ingredient, whereas some prefer using moss. The disadvantage with using large quantities of moss, peat or vermiculite is that these components have a tendency to break down and compress into a squelchy, waterlogged mass which is detrimental to pleiones’ growth.
All components in the compost should be sieved first to get rid of any fine dust particles, as these tend to settle at the bottom as a spongy layer, preventing drainage and causing the entire mix to become too sodden.
Earlier in the season, you just need to keep the medium moist enough to prevent it from getting dehydrated. This is because Pseudobulbs are not capable of taking up water or nutrients. Watering needs to be increased, that too very sparingly, only when the new roots grow. This happens only when the flowers start fading. There is no need to start feeding yet.
Watering will be increased substantially when the new leaf is fully formed. At this time you will need to start feeding too using a weak balanced feed. A dilute, well-balanced feed given regularly produces good results as plants are capable of storing excess nutrients and using them when necessary.
In hot weather, frequent watering is essential while ensuring that proper drainage is being maintained. Reduce water and stop feeding during colder periods.
During warmer spells, an evening misting over the leaves helps keep the foliage cool and increases the humidity, especially for greenhouse-grown pleiones.
While pleiones are quite tolerant about the quality of water that you use for watering, it is still a good idea to use softened water or rain water if the water supply to your area has too much of chlorine in it or if it is very hard.
During the autumn months, when the foliage starts to turn yellow, reduce water progressively and stop watering altogether when the leaves turn brown and fall off. This is to allow the new pseudobulbs to dry completely for winter storage.
Pleiones are modest feeders. From April to August, a balanced plant food is recommended at every 3rd watering at 1/4th the strength indicated on the back. A higher potash feed (at 1/4th the recommended strength) given from late August to late September will encourage the new bulbs to mature in preparation for the rest period ahead.
Stop feeding completely by October and resume normal feeding only the following spring around March.
Healthy pleiones are capable of producing at least 2 -3 new pseudobulbs every year around the base of the old bulb or around the scar that forms after the leaves have fallen off. When potted up in trays and properly cared for, these will be flowering by the 2nd year. Each bulb can potentially generate a full pot in only a couple of years.
Most pleione experts say that bulbils thrive best when mature pseudobulbs are used and this is because of the complexities involved in keeping a tray or pot of bulbils at the correct moisture level.
Ideally, Pleiones should be re-potted in fresh compost every year. When planting, ideally you need to leave 1/3rd protruding above the medium for most species. Some species require a deeper planting but it is not a critical requirement. Any remaining old tunic should be removed and old roots should be trimmed back prior to planting. Leaving about ¼” of the old roots can help anchor the bulb in the medium.
Fortunately, pleiones are not susceptible to too many pests. The only major pest that you need to keep a look out for is the Brevipalpus oncidii, which is a parasitic species of mite. To complicate things considerably, this is a microscopic species and is only visible with a very powerful lens.
The afflicted plant gradually gets weaker and weaker over several seasons with a reduced rate of increase and an increasingly higher susceptibility to rot. As the damage gets worse, it produces progressively fewer and smaller bulbs,
The most effective method to keep this pest way is by spraying specially formulated oil or insecticides. These should be applied to all pseudobulbs that are in winter storage and to the plants during the growing phase.
Another pest to look out for is aphids. These usually attack the leaves. Aphids can be gotten rid of by spraying and all affected plants should be taken out and burnt.
While fungal infections of the leaves are not very common, it is a good idea to spray routinely with a fungicide just as a safety measure.
In autumn, after the leaves have detached, the bulbs should be air dried in a cool place. It is important to keep the bulbs absolutely dry during wintering. While low levels of atmospheric humidity will not pose any problem, moisture in the compost can be damaging and when combined with cold temperatures, it could spell certain doom for the plant.