Definitions
Hardy
orchids are those that grow in the ground in temperate climates similar to our
own. They are deciduous, i.e., lose their leaves prior to a period of dormancy
and they are able to withstand frost provided their roots are not water logged.
By
this definition, Pleiones are not hardy orchids, as they require a minimum
winter temperature of +2°C and therefore would not normally survive
winters in the British Isles.
British orchids have either tubers (like potatoes) or rhizomes (an underground, horizontal stem of a plant that often sends out roots and shoots from its nodes, like the Lily of the Valley).
Life Cycles
Tuberous plants (example: Dactylorhiza): the tuber produced one year will produce leaves and, if sufficiently mature, produces flowers, seed, and then dies down and rots away. However, at the time of growing and flowering, it has produced one or more new tubers for the following year.
Rhizomataceous plants (example: Cypripedium, Epipactis): the rhizome extends
and multiplies quite quickly into a multi-stemmed plant.
Cultivation - in a Nutshell
(quote from the Hardy Orchid Society Website)
use
an open compost,
do
not allow plants to dry out,
feed
them with weak fertiliser,
shade
them on hot summer days,
protect
them from slugs and snails.
And a little more detail..
Prepare
the ground, ensuring that the soil is not too heavy and does not dry out in the
summer. On heavy soil, incorporate large quantities of compost, grit
and other materials that promote drainage. Or you could grow them in a raised
bed or in a large pot or tub where you can give them more personal attention.
Plant
them with 3 - 5 cm (1 1/2 inches) of soil above the growing tip. Cover with a
layer of mulch. In nature, they would be among grasses and wild flowers, which
would protect from direct sunlight that may burn the young shoots, also from
wind which would dry out the soil surface. It is therefore safer to plant them
facing east, west or even north, so that they don’t get scorched by the midday
sun. Inspect the soil regularly and water if it appears dry. Hardy orchids must
never dry out at the roots or they will die.
Most
hardy orchids grow happily on any soil, but some require acid soils, which is
indicated in the plant list. If you live in an area with chalky soil, the acid
lovers should be potted in large pots or tubs or in specially prepared beds
containing ericaceous compost, mixed with horticultural grit, 1 part per volume
soil to 1 part per volume grit.
In the spring, protect from slugs and snails. As plants increase, you can divide them in late summer, if needed, taking care not to damage the new underground shoots which will be next year's leaves and flowers.