Culture of Cyp. candidum


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Abgeschickt von Holger Perner am 02 April, 2004 um 09:32:10

I fully agree with Paul's notes on growing Cyp. candidum. When established at the right place (enough sun but no dry and hot conditions) it will do well and increase in the number of shoots. It is, however, not a beginner's plant, but in fact one of the trickier ones to establish. I completely failed with trying to grow it in pots for longer than two or three years. On the other side a plant which I planted in my open orchid bed in Germany did well and could be established successfully. This orchid bed was designed to house native German orchids. A part of the lawn which faces tall shrubs and some trees (i.e. the shrubs and trees grew on the south and west side of the spot) was converted into a bed by removing the turf, digging out the soil to about 25 cm or so, filling the lower 10-15 cm with building rubble (crushed limestone is nearly impossible to find in the North German lowlands, I lived east of Hamburg) and than creating a slope from the shrub down to the remaining lawn. The entire construction was surrounded by fieldstone to keep the soil in place. The slope was highest (35 cm above ground) at the shrubs and lowest (nearly level) at the lawn side. It was here towards the lawn side, were a meadow microclimate persisted in the bed. What is that? A meadow usually lies in the full sun, i.e. it gets copious light, but the plants growing in it cannot survive in hot and dry conditions. Walk bare-footed through a meadow on a hot summer day and you feel the cool and humid conditions around the plants. They protect each other from the heat and from too dry conditions and the ground is not losing much moisture by direct evaporation.


My orchid bed when it was constructed in 1991.

The richest meadows usually lie on mesic ground, i.e. have an underground with good water supply, i.e. it is not wet but also not dry. According to Charles (Chuck) Sheviak, Botanist at the New York State Museum in Albany, NY, and a profound slipper orchid specialist, such mesic conditions where the main habitats of Cyp. candidum. Nearly all of these conditions were converted into farmland (mainly fields) and only the wettest areas were not used. It is in such places, where most Cyp. candidums can be found today. But even here, where open water might stand in springtime, the plants will stand relatively dry in summer. Chuck has created an artificial prairie in his backyard where at the lowest spot a nice colony of Cyp. candidum has established itself over the years and multiplies not even by additional shoots but also by seedlings. In autumn, after the Cypripediums have died down, Chuck mows this prairie spot, or sometimes (provided the neighbors do not complain) burns it down. Thus in spring the spouting Cyp. candidum have open space and a lot of sun around them. When they start to flower, the other plants (grasses, perennials from the prairies) around them have already reached the height of the candidums, in summer they are towering high above the slipper orchids and protect them, though the latter still have copious light.

The bed I constructed is not an artificial prairie but at the lower part it houses such plants as Gymnadenia conopsea which needs open space above it and mesic soil around the roots to grow successfully, just the same conditions as I learned is necessary for Cyp. candidum. Additionally both, Gymnadenia conopsea as well as Cyp. candidum need soil with a high pH (around and above 7) for long term success (as Paul mentioned, they love lime). So I planted a Cyp. candidum close to where my Gymnadenia conopsea flourished, for esthetic reasons a Dodecatheon was placed near it (they are companions in the prairies), and it worked! The most amazing thing is, after I left Germany in 2001 this Cyp. candidum still grows on. I haven't removed it, because in a pot it would die. 


My Cyp. candidum in this bed in June 2001.

As no orchid specialist is taking care of it now (it grows in the garden of our family residence where my parents still live), I asked my mother to take care of it and make sure that enough slug pellets are spread around the candidum from spring to autumn. Slugs are a severe pest in that garden, as in all gardens where I tried to grow Cypripediums in Germany. Without constant poisoning these slimy monsters damage any Cypripedium within a few night hours. They often bring down an entire shoot over night like a beaver (they eat away the base of the shoot which subsequently fells over). I found regular sprinkling of Methaldehyd better than slug baits, the letter often starts to rot, and rotting organics around our delicate Cyps is not a good thing. I never found it necessary to apply other pesticides (like insecticides) to Cypripediums growing in the open, but in the greenhouse I had to use them sometimes when greenflies had infested some more delicate specimens. Although it is fashionable I don't think that avoiding such measures as a good insecticide approved for use in orchids or a good pesticide against slugs and snails is good for Cypripediums.

If you just have one plant, you might be able to protect it from such pests by standing beside it all night long with a torch and all day long with forceps, taking away any little creeper that wants to bite a piece off your plant or suck some of its sap, but with two or more plants you are already in trouble. With many you are completely lost, besides after a few sleepless nights you can't keep your eyes open during the day for using the forceps... But seriously, alternative methods might work under favorable conditions (very low pest frequency and few plants), they never worked with me (I don't regard Neem oil as such a fruitless alternative but rather as a good choice and natural pesticide, it worked well in my greenhouse, although with serious infestations I used artificial pesticides). However, if everything is fine, there is no need to spray the plants with some pesticide. This is not good for your health neither for that of the plant. Just like human medicine pesticides for plants should always only be used when there is a real need. And they have to be used according to the prescriptions and labels.

A last word on the substrate in which to grow Cyp. candidum in. My orchid bed was filled with crumbly forest soil from a limestone cliff mixed with some pumice. This soil was free from none-decomposed organics, i.e. it didn't contain leaf litter or bark etc. For long-term success with Cyp. candidum, which dislikes being transplanted every few years, use some inert mix. Paul uses his standard substrate which is rich in organics. Perhaps it might work, but I won't have used it in the humid oceanic climate of Northern Germany, where these materials (bark etc.) brake down soon (2 or 3 years or faster) and than the mix becomes pretty compact and damp. My Cyp. candidum grows in this orchid bed since 8 years and is still doing well in its mix, although I can only admire it over a distance of about 10,000 km (that's how far my old garden is away from my new place here in China).


Greetings from China,

Holger Perner


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