How to care for Cypripedium Orchids by Dino Zelenika Ministry of Botany

Caring for and fertilising Cypripedium (hardy slipper orchids) in spring

Cypripedium (hardy slipper orchids) are perfect garden plants in much of Europe and North America, as they are hardy to at least -20 degrees Celsius (-4 Fahrenheit). For them to grow and flower in profusion, they must be fertilised heavily in early spring, ideally just before they start growing. **Do NOT use compost, manure or other organic fertilisers. Cypripedium will rot!**

Demand for fertiliser in active growth (spring) is very high, whilst later it is low. In normal conditions Cypripedium double in size every year, quickly becoming large clumps. However, most people under-fertilise them and they remain as small plants. Failure to fertilise also leads to yellow leaves and dead flower buds, and fertilising later in the season will not fix these issues.

The easiest (and most common) way to fertilise is to use osmocote (slow-release fertiliser granules). Take off enough substrate to get to the roots and sprinkle on the recommended strength as for other garden plants. You may also use liquid orchid fertiliser as well until they start growing. I personally use Akerne Rain Mix orchid feed. Again, do NOT use compost or manure. This and other organic fertilisers make Cypripedium rot.

The substrate I use is 50% coarse perlite, 50% horticultural pumice, and just 5% good quality compost added (any higher proportion of compost and there is trouble!) I will explain more about potting Cypripedium in a future video.