Cypripedium cordigerum - plant of the month June 2017
Cypripedium cordigerum (D.Don) is found in Bhutan, Northern India, Nepal, Pakistan and China, usually in damp shady woodlands. Easily recognisable by its white pouch and green untwisted petals, the lowest (synsepal) that lies below the pouched being notched and divides into two tips (just visible on the lowest flower in the image on the left). The amount of spotting varies from plant to plant and all white forms do exist.
Specimens vary in height and can reach over half a metre in certain habitats. They are usually solitary flowered but 'twins' do occur; the pedicels coming from the same axil of the bract.
Pot cultivation is recommended in the first instance, using a mix of loam with added leaf-mold or decomposing beech or oak leaves though many growers prescribe to an 'inorganic' substrate of pumice, lava or expanded clay pellets forming the bed on which the rhizome is set ( just covering the growing point) with a thin layer of organic material above it - both methods have success and failure!
In the garden, a good crumbly open, heavy to medium soil seems to work well for many Cypripediums, especially the hybrids which are now become commercially available at reasonable cost to the average gardener. The admix of some inorganic material in the form of Perlitie, clay balls or similar helps keep the structure from over-compaction . Organic fertiliser should be avoided when dealing with Cypripediums, favouring natural forms as in well rotted leaf-mold.
Key to cultivation is never allowing the growing point on the rhizome to get either too hot or too dry during the growing season and correspondingly not too wet in late Autumn/ early Winter.