Orchid puzzle solved
A few years ago, I picked up a very cheap lady’s slipper orchid, cypripedium, at an end-of-season garden centre sale. It was just a browned stem in a pot and was labelled ‘Ulla Silkens’, a cross of the Chinese Cypripedium flavum and US native C. reginae. These glamorous terrestrial orchids can be found in the wild in North America, Europe and Asia. Ulla was left in the original pot and dug into the shady wood bed to protect it from a thuggish disporopsis. For a couple of years, she flowered, white upper petals topping a badly rouged pout. Then it was time to re-pot, which was done in my usual haphazard way, although horticultural grit was added to improve drainage. Last April, three promising fuzzy-ribbed shoots emerged. Then they wilted, so I watered them. They blackened and the plant died; I found it had rotted, probably through overwatering. Later, I came across an online article in The Orchid Review describing the correct compost mix. It gave an account of planting cypripedium following instructions to plant them in garden soil mixed with horticultural grit and either Seramis or a top-quality cat litter based on porous clay particles. The author reported that, using this method, all of the cypripedium thrived in the garden, shaded by ferns and small trees. So, it was the cat litter I was missing.
Potting up a slipper orchid using specialist compost.