This section is from the book "The Gardener V2", 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.
These Lisianths are perhaps two of the most gorgeous and showy greenhouse plants in cultivation. Though they used formerly to be considered and treated as stove-plants, yet they thrive quite as well in the greenhouse, or at least in the intermediate house.
They are both natives of South America; hence, as coming from a warm country, and before their culture was fully understood, they were, like most other exotic plants on being introduced, almost as a matter of course relegated to the stove, at least by those who did not stop to consider under what conditions they were found in their native habitats. They are found in Mexico and New Grenada, at a considerable elevation, even as high as 11,000 feet; so it naturally follows that the treatment usually accorded to plants from more temperate climes must suit them also, and such is found by practice to be the case. L. Russellianus was introduced to this country in 1835, and was so named in honour of the Duke of Bedford, who was a great patron of horticulture. It was flowered first by Mr Turnbull at Bothwell. The flowers are cup-shaped, and of a deep-blue colour, verging on purple. It is generally considered a somewhat difficult plant to cultivate, which may be the reason that one so seldom sees it among collections of plants.
To grow a good specimen of it is considered a pretty fair test of a gardener's skill as a plant-grower; but it is well worthy of more extended cultivation.
It can be propagated either by cuttings of the half-ripened wood, or be raised from seed; the latter is the more general way. The seed should be sown at the end of February or early in March. As the young seedlings are very impatient of too much moisture, which makes them damp off quickly, the pot or pan should be well drained. It is immaterial what kind of soil the pot be filled with, provided about an inch and a half or so of the top be finely-sifted leaf-mould and sand - two-thirds of the former to one-third of the latter. The seed should be sown thinly on this mixture, and pressed gently into the soil, with some flat instrument, but no cover ing of soil put over it. Water through a very fine rose, and cover the pan closely with a pane of glass, and set it in a warm pit. When the seedlings are large enough, which may be in about from six to eight weeks, they should be potted off singly into thumb-pots, and plunged in a gentle bottom-heat, being very careful of them in the way of watering. They may require a shift into larger pots about July. The soil should consist of two parts of peat, one part of good fibry loam, and one part of sharp sand, a little leaf-mould to be added, or a little good old manure.
They should be kept as near the glass as convenient, and in a warm pit, until they take to the fresh soil, when they may be removed to a cooler place, but out of the way of draughts. They may be wintered in a pit where the temperature will range at about 50° at night, and they must be very carefully looked to in the way of watering. In spring they may be again shifted into larger pots, and plunged for a time in a slight bottom-heat, in order to make them start kindly. About the middle of June they will come into flower, and so continue for a considerable time; and will form an attractive addition to the greenhouse or conservatory. L. prin-ceps is propagated in the same way as the other, either by cuttings or from seed, and it is even a more showy plant. The flowers are tube-shaped, and about 5 or 6 inches in length, of a glowing scarlet, but yellow at each end, and bulged out in the middle, the apex of each bloom spreading out into six segments, through which the anthers and pistil protrude themselves. The flowers are borne in clusters on the points of the shoots. The plant is of a compact habit, and grows to a height of about 2 feet. The general treatment given to L. Russell-ianus will also suit this variety.
J. G., W.