We tend to think to think of orchids as houseplants and most of the ones gardeners know are from warmer parts of the world. There are between 25,000 and 30,000 species of orchid found across the world. However, 10,000 of them are hardy, although Britain only has 52 species.
Many of these hardy orchids will never make garden plants because they need specialised conditions. Many are incredibly rare and endangered and removing any orchid from the wild is illegal.
However some nurseries are producing garden-worthy hybrids and these are available because of micro-propagation, a technique of growing plants in glass flasks that began in the 1960s.
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A special relationship – symbiosis
To generalise many hardy orchids produce masses of tiny, dust-like seeds and these can travel great distances on the wind. However these tiny seeds don’t have a food supply of their own. The seeds need to come into contact with a specific mycorrhizal fungus in order to germinate. Micro-propagation allows the specific fungus needed to be introduced into the growing medium so seeds, or pieces of plant material, are able to thrive. This relationship between orchid and fungi is known as symbiosis.
Despite micro-propagation hardy orchids tend to be expensive and hard to find. The following ones can do well in gardens, in the right conditions.
Dactylorhiza (marsh or spotted orchids)
The easiest hardy orchid to grow for many is the marsh or spotted orchid, Dactylorhiza, and this flowers in moist, limestone grassland in early summer. Many of the plants sold by nurseries are listed as Dactylorhiza hybrids and these flower in early summer, producing a ‘stand-to-attention’ spire of spotted pink flowers. These handsome orchids, which sometimes have spotted foliage, prefer limy conditions so they tend to thrive in areas of the country where limestone and chalk dominate.
These orchids do well in moist, open meadows and I first saw large numbers at Great Dixter in East Sussex, some twenty years ago. They were growing in fairly boggy ground close to a pond. Christopher Lloyd (1921-2006) was still alive then, however it was his mother Daisy Lloyd who had begun to plant them from the moment she moved to Great Dixter in 1910, so those orchids have been spreading and naturalising for over a hundred years. Christopher Lloyd used to transfer his top seedlings to his garden borders because they bulked up faster and then were amenable to division. This goes against the modern myth that all orchids need impoverished soil.
The bees find Dactylorhiza attractive, so these are good wildlife plants. They’re lured in by scent and the spotting on the flowers helps to guide them in. Orchids do not offer any nectar, but as a bee searches for it the orchid’s sticky pollen sacs adhere to the bee’s head and the pollen that has been deposited cannot be removed by grooming. When the bee visits another flower some of the pollen is transferred, because the flower’s stigmatic fluid is even stickier. The process is repeated and copious amounts of fine, dust-like seeds are formed following cross-pollination.
Dactylorhiza also produces tubers and every time it flowers it uses up food and at least one tuber shrinks. It’s important to keep hardy orchids in leaf for as long as possible and this is easier in moister soil. If you do have to water your plant in its first year, use tap water if you can, because this is limier. Copious amounts of seeds blow around in the wind in late-summer and, if you’re lucky, you will get more plants because the ground nearby is likely to contain the correct fungus. A seedling takes 3-4 years to flower. Cold winters can stop tuber growth and this may affect flowering.
Hardy dactylorhiza orchids do well with other British wild flowers in a mini-meadow or bigger area of grassland for instance. They return year after year if happy.
Find out how to grow British wildflowers
Yellow rattle (Rhinanthus minor)
A hemi-parasitic annual with hooded yellow flowers.
Sweet vernal-grass (Anthoxanthum odoratum)
A very stiff-stemmed and aromatic grass forming tight, cylindrical heads.
Hop trefoil (Trifolium campestre)
A legume with creamy, spherical heads held above the ground.
Lady’s bedstraw (Galium verum)
A lover of poor soil, this produces an acid-yellow froth that’s floppy – setting off the purple orchids.
Meadow vetch (Vicia cracca)
A willowy vetch with a long head of purple flowers.
Bird’s-foot trefoil (Lotus corniculatus)
A compact member of the pea family with clusters of red and yellow flowers – often called eggs and bacon.
Meadow Vetchling (Lathyrus pratensis)
A perennial, twining member of the pea family with pale-yellow flowers.
Where to buy Dactylorhiza
Laneside Hardy Orchid Nursery www.lanesidehardyorchids.co.uk
Beth Chatto www.bethchatto.co.uk
Plants for Shade www.plantsforshade.co.uk
Cypripedium (slipper orchid)
Slipper orchids have shoe-shaped flowers in shades that include pink, yellow, brown and white. The yellow and brownish-yellow flowered forms are said to be easier than the pinks and whites, because most yellow hybrids contain the easiest North American species. These rhizomatous orchids are found naturally in China and North America. There are 32 Chinese species and 12 American species found on woodland edges. The Asian ones like summer moisture and may need watering in dry periods, however drainage must be good in winter.
We have a species of native lady’s slipper orchid (C. calceolus) found in in Northern Britain, but it almost became extinct. It grew in one heavily guarded site. However it has now been replanted on 16 sites across Northern Britain following work carried out at Kew Gardens with the backing of the Sainsbury’s Orchid Conservation project. Work began in 1983 and they have raised more by micro-propagation.
Raising other Cypripediums in bulk
Within the last ten to fifteen years, Dutch nurseries have begun to produce slipper orchids in quantity. They do this by feeding them every 3 to 4 days, using an orchid feed. Rain Mix is recommended by one grower. This method produces large plants that can then be divided in autumn. Previously large numbers were being dug up in the wild, although they rarely went on to grow into good garden plants because the roots had dried out too much. They’re far easier to find and prices start form £25.00 per plant.
What Cypripediums to grow
The easiest species is C. reginae, from North America. This is also known as the Showy Lady’s Slipper orchid, because the large flowers are white and deep-pink. In the wild it often shares a boggy site with the Royal fern (Osmunda regalis) so this cypremedium could be used as a bog plant as long as it’s planted above the water line. Other recommended North American varieties include C. kentuckiense and there are hybrid forms from this and they include ‘Kentucky Pink’ and ‘Kentucky Flush’.
Hybrids are often stronger and easier to grow. ‘Hank Small’, a hybrid between C. parviflorum x C henryi, is one of the more available ones and it has an AGM. The bright-yellow slippers are framed by narrow, twisted maroon-brown tepals.
Cypripedium hybrid 'Pixi'
Easily grown hybrids recommended by Laneside Hardy Orchids
Gold, early, usually two flowers on a stem, bulks up quickly. 25cm
Gold and brown, early flowering, small flowers, bulksup well. 25cm
Very dark black red flowers May, bulks up well. 30cm
Cream with red across pouch, large flowers, bulks up well early flowering. 35cm
Cream with pink blushes on bowl, large flowered, late flowering. 40 cm
White with variable spots on bowl, late flowering 40cm
Orange with red overlay, medium sized flowers, May flowering. 35cm
How to grow Cypripediums
A north-facing position can often be right for them, or a spot that gets two or three hours of morning sunshine in spring and summer.
It should be a cool, semi-shaded position and you can either sink the pot into the ground, or add grit, perlite, some dolomite dust and some fine potting bark as you plant. The most successful growers seem to use well-drained raised beds.
Water in the first season if needed, using tap water.
Protect from slugs and snails.
Do not feed them.
Where to buy Cyripediums
Haperley Hall Farm Nurseries www.harperleyhallfarmnurseries.co.uk
Laneside Hardy Orchids www.lanesidehardyorchids.co.uk
Jacques Amand www.jacquesamandintl.com
Key growing tips for all hardy orchids
Always start with a healthy plant rather than a tuber or root.
Water with tap water.
Don’t feed them – hardy orchids prefer a poor diet.
Buy hybrids, they have extra vigour. Some have an x in their name, eg Dactylorhiza x grandis. Others have a name in single italics eg ‘Pueblo.’
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