This section is from the book "The Gardener V3", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
It has often occurred to me that these plants should be more generally cultivated than is at present the case, more especially as many of them are, when well grown, scarcely less beautiful than the more expensive Epiphytes of our Orchid-houses. I am induced to make a few remarks after reading the practical letter of your North Wales correspondent in last month's 'Gardener.' "G. G." may certainly congratulate himself on having been so successful as to flower a large number of the Italian species received by him under such unfavourable conditions. Terrestrial Orchids ought, as a general rule, never to be disturbed when making their growth, or in the flowering state • still I know from experience that many gardeners continually receive them from their employers or their friends, who happen to be travelling on the Continent when these beautiful plants are in flower. The best way of collecting these plants is to mark them when in flower, and afterwards to remove them when the foliage has died off, and the tubers are thoroughly ripe and dormant. They (the tubers) should be carefully packed in moist earth or sphagnum during transit, and must be potted off as soon as received at home.
The soil best suited for their requirements is strong fibrous loam, with a mixture of leaf-mould and coarse sand; other species, as many of the Ophrys and Cypripediums, affect a chalky soil, or lumps of limestone may be broken and mixed •with the fibrous or turfy compost. The pots should be well drained, and the soil pressed firmly around the tubers, after which plunge the pots in ashes, sand, or cocoa-nut fibre, in a cold frame, where they may remain all winter; all the attention they will require is to keep the soil moderately moist, nothing being more injurious than to let them get dust-dry. In a state of nature all bulbs and tubers get a copious supply of water during the winter season, or while they are at rest; and I have often thought that the reason many cultivators fail in growing these plants is, because they dry them off during the winter months. The pots should be protected during heavy rains and severe frosts, either by having the glazed lights drawn on, or an oil-cloth spread over the pit or frame in which they are plunged.
The foregoing instructions may be followed out in the case of rare or delicate Continental species; but many of the British and American species may be planted out in the rock-garden or herbaceous border, and will in most cases be found to succeed to perfection. One of the most beautiful of all hardy terrestial species, Cypripedium spectabile, grows vigorously planted out in a peat-bed on a cool clay bottom; while our only British species, C. calceolus, grows best in a chalky loam, fully exposed to the east, but sheltered from the mid-day sun. In Messrs Backhouse & Son's nurseries at York, these two beautiful species grow vigorously and flower profusely every summer, along with many species of Orchis and other Continental Orchids. When these plants are grown outside, select a partially shaded spot well furnished with other herbaceous plants, and plant the tubers 5 or 6 inches below the surface; they will find their way through in due time, and will not suffer from the vicissitudes of the weather as they would if planted just below the surface of the ground. The contiguity of other herbaceous plants prevents undue evaporation from the soil in which they are planted. During winter a mulching of short litter, leaves, or manure, will protect them both from frost and cold rains.
I sincerely hope these beautiful plants will meet with every encouragement in our gardens, for amongst terrestrial Orchids there are many species not yet introduced to our collections that will bear comparison with the choicest Epiphyte in point of beauty and fragrance. At the same time they may be grown without the unpleasant heat and extra labour required by tropical species from hot countries. I wish your correspondent "G. G." every success with his terrestrial Orchids, and hope that other horticulturists may be induced to attempt the culture of hardy Orchids, and that, like "G. G.," they will frankly favour us with practical notes of their experience. B.