Getting to Grips with Hardy Orchids

I can see a new addiction coming from a mile off, so on the whole I steer well clear of orchids. Over the ages thousands of plant collectors have been consumed, even broken, by their passion for orchids and I do not wish to join their ranks. Hence they are the only family of plants I spend more time reading about than growing. And whilst I find orchids beautiful and endlessly fascinating, I have not found growing them myself either easy or satisfying – that it, until I discovered hardy orchids.

It all began with pleione, otherwise known as peacock orchids. These pretty terrestrial orchids from China and Taiwan are simplicity itself to grow, provided a few simple rules are adhered to. Pleione are forest-floor dwellers, so they like cool, damp, shaded conditions and a deep carpet of fallen leaves, mosses and twigs to sink their roots into. I lost most of my fledgling collection in the process of moving from London to Broadstairs, so currently it’s just me and a hybrid called ‘Clare’ living side by side at The Watch House. Clare has white flowers with a lemon-yellow throat from March until the end of April and she spends nine months of the year outside. Considering how tiny the pseudobulbs are, pleione flowers are large, intricate and surprisingly robust. It’s easy to get hooked.

Pleione formosana growing in my old London garden

Larger hardy orchids such as calanthe, cypripedium, dactylorhiza and bletilla have never been on my wish list since I assumed they needed to be planted somewhere cool and woodsy, not in dry chalk or pots. But last year I saw some fine Madeiran orchids (Dactylorhiza foliosa) growing in a pot at Marshborough Farmhouse and wondered if this might be an option for me. As luck would have it, our local garden centre bought a small lot of mixed hardy orchids from a Dutch nursery and I decided to invest in two plants; one a calanthe (Christmas orchid) and one a cypripedium (slipper orchid). Since I am not keen on having plastic pots on display they were both immediately repotted in terracotta using a proprietary orchid compost. I think this was meant for tropical orchids, but the result so far are encouragingly good.

Dactylorhiza foliosa at Marshborough Farmhouse, Kent

The basic principles of hardy orchid cultivation are straightforward. Almost all orchids that are hardy in the UK are terrestrial – that is they grow in the ground, rather than in trees. They tend to colonise habitats with low or restricted nutrients, for example chalk downland or dune slacks. Many hardy orchids have also adapted to endure periods of drought and deprivation, which is why they go dormant, often for long periods. (My Cornish grandmother had orchids in her lawn and they only started appearing regularly after she became too elderly to keep it well mown.) Mollycoddling, the default behaviour of many an anxious or inexperienced gardener, is exactly what hardy orchids don’t appreciate.

Calanthes come in a wide variety of colours, all producing abundant flowers.

Each genus has slightly different needs in terms of soil pH, watering and sun / shade in order to thrive. Cypripediums (slipper orchids) like free-draining soil and protection from midday sun. They also like to be cool in summer. C. reginae from North America is considered to be one of the easiest slipper orchids to grow. They prefer a damp spot and a free root-run, although they will grow happily in pots positioned outdoors or in an unheated greenhouse. Calanthe (Christmas orchids) originate from Japan, where they can be found in woodland habitats. Their needs are more similar to hostas and ferns in that they prefer an open, woodsy growing medium and cool summer shade. Calanthe are semi-evergreen, meaning that the previous year’s foliage needs to be removed in early spring before the new leaves and flower spikes emerge. Being fully hardy, calanthe can be planted in the ground if you can provide the right conditions, or in a pot, which is what I have done. Provided the plant is sheltered, the flowers will last for weeks.

Pleiones appreciate a mixture of bark and moss in which to grow.

Pleione (peacock orchids) come from temperate regions of China and Taiwan where they experience pronounced seasons, as w do in the UK. However they can’t be considered quite as hardy as the other orchids I’ve written about in this post. They need to be kept frost free, which I manage by stashing the tiny pseudobulbs in the workshop and forgetting about them over winter. Pleione are usually cultivated in pans (low pots) because of the their small size and relatively high value. One can pay a lot of money for a single flowering-size pseudobulb of a less ordinary species or hybrid. They require a very open and free draining compost – ideally 3 parts bark and 2 parts moss. This mixture does seem improbably light and airy when you go to plant your precious pseudobulbs, but it works like a dream. In summer I shove the pans, by now filled with long, attractive, crinkly leaves, somewhere cool and shady. I hose them down every so often and let them drain thoroughly.

For a sunny spot, marsh orchids (dactylorhiza) are the obvious choice. The Madeiran orchid, D. foliosa is a handsome beast and strong enough to hold its own in a pot, or a herbaceous border. If planted in a container, make it a large one so that it can be left undisturbed for a number of years. The Madeiran orchid produces substantial spikes of magenta-pink flowers up to 80cm tall and forms a large clump quickly. There are marsh orchids for almost every soil type. In alkaline conditions the Southern marsh orchid D. praetermissa with thrive, whilst in acidic soil the Northern marsh orchid, D. purpurella is well suited. Bletillas (urn orchids) from the Far East will take full sun or semi-shade but require that holy grail of soil conditions – moist yet well-drained. If you are a fan of tropical orchids then the urn orchids are with their graceful sprays of flower – they appear far more delicate and exotic than they actually are. The species you are likely to find in your local garden centre is Bletilla striata, the Chinese ground orchid. It is perfectly nice but you’ll have to search quite hard if you want to find other species or a named variety.

Calanthe discolor.

The main drawback of hardy orchids is that they are expensive to buy and that is a deterrent for some gardeners. They are expensive mainly because they are tricky to propagate. Orchid seeds are like dust and have no endosperm – that is the part of the seed that normally provides the embryo with food. To grow they need to form a symbiotic relationship with a mycorrhizal fungus that provides the sugars, nutrients and hormones required to germinate, or to be sown in a laboratory where these can be supplied artificially. Most hardy orchids take 6-8 years to flower when grown from seed, which is what you are paying for. Added to which the majority are not in the horticultural mainstream, so anything out of the ordinary tends to be produced in very low numbers by just a handful of nurseries. Laneside Hardy Orchid Nursery, here in the UK, is a very good source, selling at flower shows and from their website.

All I would say is that you should not let the price tag put you off, or suggest to you that hardy orchids must be ‘specialist’ (i.e. difficult). They are perfectly easy to grow, even in small gardens and unheated greenhouses. A little protection from the worst of the weather will reward you with longer-lasting flowers. I keep mine on my outdoor kitchen worktop where I can enjoy the flowers close up. Very soon you’ll be wanting to try more, although not, I hope, developing an addiction to these mesmerising plants. TFG.

Southern marsh orchids, Dactylorhiza praetermissa, growing in St Agnes, Cornwall.