We pass now from the consideration of stately members of the order Amaryllidaceae to some of the tuberous perennials from Mexico, Jamaica, etc., that, while able to do with a temperature of 550 from September to March, require one of 650 to 8o° from March to September. They are of the botanical order Gesneriace‘, and the first is called Gesnera zebrina discolor. Not only are the flowers orange-scarlet, but the leaves are claret colour, marbled with other hues. Then there are quantities of Hybrid Gesneras, with blossoms of yellows, pinks, mauve, purple, or white. Stay! - the merits of this plant are not yet explained. It is easy never to be without blossoming specimens, given the correct temperature. Bulbs or tubers are not costly, may be potted 1 inch deep, singly, in five-inch pots, or 2 inches apart in larger ones, in March for summer bloom, in May for autumn, in June for winter, in September for spring. When not to be potted at once tubers should be wrapped in several thicknesses of paper and put into a tin box. Those used in September and March should have a few hours' soaking in tepid water first. Use a compost of equal parts of peat, loam, leaf-mould, and coarse silver sand, with quarter parts of old cow-manure, hop-manure, and crushed mortar.
The pots must stand uncovered in the greenhouse, not in full sunshine, and the soil must not be quite dry. When growth appears watering must be moderately done, a good deal being required by blossoming specimens; after flowers are over watering is lessened, and stopped as soon as the foliage dies down, After this, the pots should be laid on their sides on a dry shelf, in a temperature not above 550, until the time of year at which their bulbs were originally started. Then the bulbs should be carefully taken out, soaked for half a day or so and repotted.
The height of plants is from 10 inches to 2 feet. Achimenes, which belong to the same order, and come from the same countries, are from 6 to 24 inches tall, of all colours nearly, for the blues are especially effective among purples, violets, yellows, reds, pinks, and crimsons. Give Achimenes a compost of equal parts of peat and loam, half-parts of leaf-mould, decayed sheep-manure, and fine silver sand. Put three tubers, 2 inches deep, in each five-inch pot. Otherwise treat like Gesneras. They are very attractive sunk in hanging baskets. To hasten their culture the pots may be plunged into a hot-bed, to start bulbs into growth.
Then there are Tydaeas, of rose, crimson, yellow, purple and blends, with charming green or ruddy crimson leaves. The rhizomes may be placed 1 inch deep, three in a six-inch pot, of the same compost as for Gesneras, at the same seasons, and given similar treatment, except that a temperature five degrees or so higher is needed, and shade must be arranged. Owing to the last essential Tydaeas are delightfully suitable to grow among hot-house ferns, where their bright hues supply a need.
Let us close this chapter by noting the culture necessary for Greenhouse Cyclamen, which have been called at once the simplest and the most difficult of the almost hardy plants to grow.
Watering correctly is the great secret, and gardeners do not agree as to this, for some hold that there is no reason why plants should be dried off at all. However, the old method will suit the amateur best.
While Cyclamen are frequently raised from seed, and grown on patiently till of flowering size, the best plan is to buy corms and pot them, just resting in the soil, not covered, any time from July to the beginning of September, and singly in four-inch pots. Use a compost of one part of fresh turf loam, with half parts of clean sweet leaf-mould and coarse silver sand, adding to the mixture a good dusting of bone-meal and many pea-sized bits of charcoal. Keep in cool shady position with plenty of air, and do not allow compost to dry up, though the corms will rot if there is excess of moisture. When plants are about to bud, move the pots into a temperature not above 550, out of sunshine. After flowers are over water is gradually withheld, and the bulbs must be kept dry but cool, in the pots, till the time of year at which they were first started. Repot then, and try cultivating the same plants a second year.
No doubt it is the delicious scent of the Cyclamen that makes it such a favourite greenhouse plant; the dark-green leaves, with red-pink stems often, are ornamental even when there are no blossoms: the flowers come prodigally and obtain great size, from prize strains, besides offering rare shades of rose, salmon, lilac, magenta-scarlet, etc. There is a kind with frilled petals, another fringed.
It must be recollected that nearly all bulbs have to be freed, sooner or later, from their offspring - the offsets, or bulblets, that rob nutriment from the parent. One may go on top-dressing big bulbs, repotting, etc., but the time comes when a more drastic treatment becomes essential.
Lily Bulb in Need of Division.
While the removal of portions of fresh bulbs is easy to understand - say from a Lily clump - the inexperienced gardener dreads interfering with such possessions as Hippeastrums, Clivias, Nerines, etc., yet their absence of, or insufficiency of, bloom is frequently the result of a lack of space.
Perhaps, therefore, it would be well for the timid cultivator to engage the services of a nurseryman owning hot-houses - say every fourth year.