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.
We have here a genus of plants from the highlands or mountain-ranges of the New World, and particularly noted for their adaptability to what is popularly termed "cool treatment." Nearly all the species of this large genus are very handsome, neat in habit, and bear a rich profusion of blossoms.
Odontoglossa are favourites with most Orchid-growers, as they may be grown without any great expense either for fuel or labour. The best erection in which to cultivate these plants is a low span-roof house or pit. The house need not be more than 8 feet high in the centre, and the side walls 5 feet. The breadth of the house may be 12 feet; this gives 4 feet for the side benches or tables and 4 feet for the path. Provision must be made for thorough ventilation, covering the openings with perforated zinc or wire gauze so as to exclude cold currents of air or draughts. A house of these dimensions, and 40 to 50 feet in length, is heated sufficiently by a flow and return pipe passing round it under the side benches. Or in other words, a house in which these plants may be grown perfectly, requires no more piping than is considered necessary for heating an ordinary greenhouse. The benches should be of slate, on supports of either iron or wood, the former being preferable on account of its durability. These benches should be covered either with Derbyshire spar, or cannel-coal broken up into small nodules, upon which the pots can be arranged.
Cannel-coal always appears clean, and the dull black colour is not at all conspicuous, while it efficiently answers every purpose for which spar or shells are used. Most Odontoglots grow freely in a compost of fibrous peat, some dried horse-droppings, chopped Sphagnum, moss, and sand. The pots must be thoroughly clean and dry, and plenty of drainage must be used, in order that all superfluous moisture may pass away readily. Odontoglots require an abundant supply of moisture when in a healthy growing condition; but, like other plants, they are injured by stagnant rottenness at the root. We will now glance at those species best worth cultivating for their winter-flowering qualities.
This is one of the most beautiful species in the genus, and deservedly popular with Orchid-growers. Its flowers vary from pure white to white suffused with rosy lilac, and heavily blotched on the lip and sepals with brown. A remarkably fine specimen flowered at Meadow Bank some time ago bearing 120 flowers, 56 of which were borne on one spike. I saw many plants of this species growing in a brick pit at Meadow Bank last summer, and they were in very fine condition; while the expense of cultivation would not be more than that of greenhouse plants in general. This species should be grown by the dozen where there is convenience, as where a good stock is kept, it may be had in bloom throughout the year with but little intermission. Its flowers last a long time in beauty. After potting, this and all other Odontoglots should be surfaced with a layer of fresh green Sphagnum, which not only conceals the compost and gives the pot-tops a clean and fresh appearance, but also maintains an equable state of moisture at the root.
This is not so showy as some species, but highly interesting, and worth cultivating for variety in a collection. Its flower, spikes are slender, often branched, and the flowers yellowish, heavily blotched with purplish brown. The crest of the lip is white, and in some varieties a large proportion of the lip is also white. It flowers freely during the winter, and lasts a month or six weeks in perfection.
A very pretty dwarf species, often known in gardens as 0. membranaceum, introduced from Western Mexico in 1845. The plant has small, angular, one-leaved, pseudo-bulbs, and produces a flower-spike from 4 to 6 inches long, bearing four or five delicate membranaceous flowers, more or less of a soft rosy colour. The bases of the floral segments are marked with transverse bars of brown or brownish crimson, lip white. It is a pretty little species, well worth growing, and lasts from three to four weeks in flower.
A distinct species found in Mexico and Guatemala, and introduced to this country about 1837. In bulbs and foliage it somewhat resembles 0. maculatum, but is very distinct from that species when in flower. It bears numerous erect spikes of flowers when well established, sepals and petals about 1 1/2 inch long, lanceolate, the apices being attenuate and often wavy. In colour they are very remarkable, being heavily blotched with a dark brown (of peculiar richness in some varieties), on a ground colour of pale greenish yellow. The lip is heart-shaped, of a white colour, blotched, and often margined with brown, and furnished with a pubescent bilobed crest.
This species flowers very profusely during winter and spring, lasting from three to four weeks in perfection.
This is an old but at the same time truly magnificent species, blooming during the autumn and winter months. This species, together with 0. Insleayii, 0. citrosmum, 0. Krameri, 0. Phalsenopsis, likes a few degrees more heat than the generality of Odontoglots, and will be found to succeed better in a Cattleya house, or in an intermediate temperature, rather than in the cool house. 0. Phalamopsis is especially sensitive to either extremes of temperature or stagnant moisture. Well-established plants of 0. grande make fine subjects for exhibition, and produce a profusion of their great golden yellow, heavily blotched and barred flowers. No other Odontoglossum is so effective as this when well grown, and it has the good quality of retaining its gorgeous beauty for a considerable period.
We have in cultivation several forms of this plant which are frequently sold and named 0. radiatum or 0. Hallii. It is a fine plant, and good specimens bear from twenty to thirty flowers on a spike 4 or 5 feet long. A fine specimen of the "Hallii variety " flowered at Ferniehurst, bearing thirty flowers, some of them 3 1/2 inches across, on a branched spike nearly 5 feet long. Three smaller spikes were borne by the plant at the same time. The sepals and petals vary greatly in breadth in different forms, and are of a yellow colour heavily blotched with brown. The lip is broad, with a white fimbriate margin, the disc being blotched with brownish crimson: some varieties of this plant are very richly coloured.
This is another fine winter-flowering species from Mexico, somewhat resembling 0. grande in habit. It is a very free-flowering species. Sepals and petals yellow, barred with brown. Lip of the richest golden yellow, often spotted with crimson. It flowers all through the dull season of the year, and lasts in beauty from three weeks to a month.
This is a lovely species, and, like its congener 0. Alexandrae, blooms at different times during the season. I have recently seen it in great beauty in several places, and its pearly blossoms are doubly valuable at this dull period of the year. There are several varieties of this species, some nearly pure white, others spotted and blotched with dense purple, but all are beautiful. I measured a flower with Mr Denning in Lord Londesborough's fine collection, and found it fully 3 inches across. This is one of the finest varieties I have seen, its sepals and petals being very broad, and of good substance and colour. This plant roots vigorously in the compost above named, and grows well in the cool house. It was introduced from New Granada about 1851, and is one of the finest species in this beautiful genus. It lasts from three to five weeks in flower.
This is a pretty little white flowered species from Mexico, and was introduced some time before 1841. There are several varieties of this plant, some bearing spikes of flowers very little larger than Convallaria majalis (Lily of the Valley), while others bear flowers an inch in diameter.
The sepals and petals are of a pure crystalline white colour. The lip is bent nearly at right angles, and has a crest shaped like a W, of a golden or lemon-yellow colour spotted with crimson. The delicate flowers are borne nine or ten together on erect spikes, among the dark grass, like leaves. It is a profuse bloomer when thoroughly established, and its fragrant flowers come in very acceptably for bouquets. It lasts a month or even six weeks in perfection.
This, like 0. Cervantesii, is a very dwarf species. Still, one variety bears very fine flowers; its blossoms are borne two or three together on a spike 5 or 6 inches long. Sepals of a creamy white colour, spotted or blotched with purplish brown; petals broad, pure white, barred transversely with purple. Lip pure white, with a golden crest. This pretty little species should be in every collection. It flowers about this time of the year or a little earlier, and lasts about a month in flower. The best variety is known as 0. Rossii superbum in gardens.
This is a very rare plant, and at the same time one of great beauty. It may be considered the best of the yellow-flowered section, if we except 0. grande. The flowers are 3 to 4 inches across, borne on a nodding spike. Sepals and petals of the richest golden yellow, blotched with brown. Lips white, with a golden crest, and the apex tipped with rosy purple. This is a very valuable plant, blooming at different seasons, but generally during the winter and spring. The habit of this plant somewhat resembles that of 0. Pescatorei, and the bulbs are sometimes spotted with brown as in that species.
This plant has great fat speckled pseudo-bulbs and broad foliage, and is altogether very distinct, both in habit and flower. Like most other Orchids, it varies considerably in the size and colour of its flowers, some varieties being very richly tinted. Sepals and petals yellowish green, more or less heavily blotched with purple brown. Lip broadish, cordate, of a white colour mottled with rose. This plant grows well in the coolest house, but requires an abundant supply of moisture nearly all the year.
It bears ten to twenty flowers on spikes from 2 to 3 feet long, when well established and in good health. Guatemala.
This is another species from Guatemala, having been introduced in 1837. It bears numerous erect spikes during the winter and spring months. These spikes are from 18 inches to nearly 3 feet high on good specimens, and bear fifteen to twenty flowers, which open in gradual succession. Flowers about 1 inch across, of a yellow colour blotched with brown. Lip often white, sometimes of the deepest rose. It sports into several varieties, the best of which are very ornamental. F. W. B.