CHAPTER XVIII
GREENHOUSE AND STOVE BULBS
Lachenalias – Nerines and Lycorises – Pancratiums and Hymenocallises – Richardias – Sprekelias – Tuberoses – Vallotas – Watsonias – Zephyranthes
Lachenalias
Were the beauty and usefulness of the Lachenalias better known, they would soon become very popular plants for the amateur's greenhouse and window. They may be said to lie on the border-line between greenhouse and frame plants, as only sufficient heat is needed to keep out frost. The popular name of "Cape Cowslips" gives some indication of the appearance of the spikes of drooping flowers, but hardly expresses the singularly pretty colouring, which lies in the yellow or white grounds and the shadings of green, red, or purple, which make such pretty combinations. The Lachenalia, which can be had in bloom from February to May, requires a period of rest, and after flowering the pots should either be placed on a sunny shelf or other dry place, and water gradually withheld as the leaves become yellow. Pot in August in loam, leaf-soil, or peat, and a little manure and sand. Some grow Lachenalias in hanging baskets lined with moss and filled with soil. A good selection may be made from the following, but the newer varieties are well worth having also, although a little more expensive. A selection: – fragrans, lilacina, Nelsoni (hybrid), pendula, tricolor, tricolor lutea (syn. L. aurea). New varieties are Aldborough Beauty, Cawston Gem, and Rector of Cawston.
Nerines and Lycorises
The best known of the Nerines is N. sarniensis, the Guernsey Lily, which is imported in great numbers in autumn with the flower buds set, and is potted at once to bloom almost immediately. It has been grown by some as a hardy or half-hardy bulb, but its true place in most gardens is in a greenhouse in pots. This is advisable so that it may perfect its foliage. It likes a rich, yet light, soil and careful watering.
It is unfortunate that some of the other Nerines are not more grown, as their brilliant flowers possess all the beauty of the better known sarniensis. The handsome scarlet curvifolia, with its even finer form, known as Fothergilli major, are worth more than the room and care they need. Then the rose-coloured flexuosa; the rosy carmine humilis splendens; the white and red pudica; the rosy-purple undulata; and the hybrid or seedling forms, amabilis, carmine rose; the charming roseo-crispa, pink; and excellens, bright rose, are all of much beauty. These should have little water from May to August. The Lycorises should be cultivated in a similar manner.
Pancratiums and Hymenocallises
These closely allied plants require similar treatment, and may be suitably mentioned together. The connection is so close indeed that several of the species of either bear in gardens the generic name of the other. The stove species should always be kept moist, while the plants which do with greenhouse temperature need to be kept dry while at rest in winter. The pots must be large and filled with good loam and leaf-mould, with a dash of silver sand. The bulbs should be just below the surface. A few, which have been also known as Ismenes, are understood to be hardy in favoured places. Ordinary stove heat will suit the following: – Hymenocallises: – andreana, Choretis, expansa, lacera, ovata, macrostephana, maculata, speciosa; and Pancratiums verecundum and zeylanicum. For the greenhouse there are: – H. Amancaes, calathina, harrisiana, littoralis (syn. adnata), macleana (the hardiest), tenuifolia. In looking over catalogues to order these, Pancratium, Hymenocallis, and Ismene should all be referred to on account of the uncertainty about the nursery names.
Richardias
These are best known because of the popular R. africana, often called Calla æthiopica, the Arum Lily, or Lily of the Nile. All the species like a very rich soil, and a plentiful supply of water while growing. R. africana can be grown as a hardy aquatic in some warm districts in these islands if the crowns are well below the depth to which the water is frozen. It is, however, most grown as a greenhouse or window plant, especially when white flowers are wanted early. After flowering, it may either be planted out in trenches in the garden, or dried off and started in the same pots. Potting may be done about September, and the plants grown in ordinary greenhouse temperature. Albo-maculata, hastata, and melanoleuca are less beautiful. Adlami, elliotiana, Pentlandi, and Rehmanni are all newer and of much beauty, the second and third having yellowish flowers.
Sprekelias
Although Sprekelia formosissima, known also as Amaryllis formosissima, the "Jacobea Lily," is sometimes recommended as a half-hardy bulb, this is of doubtful expediency, and it is better to treat it as a cool greenhouse bulb and to grow it in pots. It is sometimes planted out on a sunny border below a wall in April and lifted in September, but we recommend planting it in turfy loam, well-decayed manure and a little sand, in pots, and treating it like the Hippeastrum, but in a rather lower temperature. It grows about two feet high, and has crimson or white flowers about June. There is another named S. Cybister, which has red flowers about April.
Tuberoses
The botanical name of the Tuberose – Polianthes Tuberosa – is so little used by those who grow it that it will be more convenient to speak of this most fragrant flower under its popular title. It is everywhere prized, especially when its pure white flowers are produced in winter, when few of similar character for buttonholes and bouquets are readily procurable. Although a plant which can be flowered in the open border if the bulbs are started and grown on for some time under glass, it requires a considerable amount of heat to flower it properly at other seasons. The bulbs should be potted three together in a five or six inch pot in a soil composed of loam and manure or some leaf-soil. The soil should be slightly moist, so as to obviate the necessity of watering before the bulbs begin to make growth. Some plunge in a cold frame until growth begins, but a preferable plan is to plunge in a bottom heat of from sixty to seventy degrees if early bloom is required. Plenty of water should be given when growth has fairly begun, and it can hardly be too strongly emphasised that this and a temperature such as that named for the bottom heat should be maintained for winter-blooming. Potting may begin in November, and may be continued at intervals for two or three months. Old bulbs are not worth keeping. The double form is the more appreciated, and the double African, American, and Italian grown bulbs are all good. The Pearl is dwarf in habit.
Vallotas
The Vallota, or Scarborough Lily (V. purpurea), is a general favourite for its brightly coloured flowers in autumn, and because of the ease with which it can be grown in a greenhouse or window. It is hardy in a few favoured places, and in some is grown as a frame bulb, but for the greater number of British gardens it is best when grown in a house from which frost is excluded in winter. It should be repotted as seldom as possible, and then the roots should be little disturbed and the plants transferred to a larger pot with the ball attached, only removing some of the soil on the surface to allow of top dressing. The offsets may be removed with a stick. It likes a rich, light soil, and may be potted towards the end of spring. The roots should never become dry. Some give a little liquid manure during summer, and when well grown few plants look more ornamental, with its heads of deep scarlet flowers. There is a larger-flowered variety named major.
Watsonias
Although the Watsonias will do if planted out on a warm south border in favoured places in this country, and treated as half-hardy bulbs, intending growers are advised to grow them in pots as greenhouse plants. They have fine branching stems of a height of from two to three feet, and pretty blooms somewhat resembling those of the Freesia in form. The corms should be planted in spring, and treated like Gladioli in pots. After flowering, water should be gradually reduced when the leaves begin to turn yellow, and the corms either kept dry in the pots or taken out and stored like those of the Gladiolus. The most appreciated of the Watsonias are the varieties of W. Meriana, the type form having rose-red flowers. The white varieties of this, such as alba, Ardernei, and O'Brieni are all much admired, that called Ardernei, which some consider the same as O'Brieni, being a special favourite. W. M. iridifolia and W. M. roseo-alba are also good varieties. Other desirable species procurable are: – aletroides, scarlet or pink; angusta, scarlet; coccinea, crimson; humilis, rose-red; and rosea, rose-red.
Zephyranthes
All the Zephyranthes mentioned in the chapters regarding hardy and half-hardy bulbs can be grown in the greenhouse, and there are also a few which ought to have a little additional heat, such as that of a stove. Citrina, yellow, about six inches high, and blooming in August, is one. Others are concolor, sulphur-yellow and blooming in April on stems a foot high; pumila, also known as Habranthus pumilus, blooming about September, and having rose coloured flowers; robusta (syn. Habranthus robustus), about ten inches high and blooming in June; sessilis, white and red, with its flowers in April; striata is a striped variety of this; tubispatha likes stove heat. They grow best in turfy loam, with the addition of some decayed manure or peat and sand.