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Greenhouse Bulbous Plants

Amongst these, a great diversity and selection are available for cultivation, and numerous beautiful plants are included. Apart from the value of Dutch bulbs for forcing and spring decoration, nearly all the various species from the Cape succeed under Greenhouse treatment, and are highly ornamental when in flower. The majority may be grown in a sandy soil, and in comparatively small pots. Most Cape bulbs should be encouraged to make their growth in a moderately warm house or pit, and then be allowed a season of rest in a cooler place before flowering. In addition to Hyacinths, Tulips, &c., the following are amongst the best of Greenhouse plants generally termed "bulbous," but some of them are in reality not so: Babianas, Begonias (of the tuberous section), several Crinums, Cyclamens, Freesias, Gladioli, Ixias, Lachenalias, Liliums, Narcissi, Nerines, &c. The foregoing, with many others, are well adapted for pot culture, and well repay for any special attention devoted to them.

Arrangement of Flowering Plants, &c. In Greenhouses retained more for the exhibition of plants than for their cultivation, a method of arrangement should be adopted by which the whole may be rendered attractive, and, at the same time, sufficient space allowed each plant to enable it to be properly seen. In span-roof houses, there are usually side stages, and, if large enough, a central one, or otherwise a bed, nearly level with the floor, forms the centre. The latter position, in either case, should be devoted to the taller-growing plants and evergreen shrubs, interspersed with a few in flower, according to the stock at command. Formal arrangement should specially be avoided, the flowering subjects being evenly dispersed throughout, and, so far as practicable, plenty of plants with green foliage intermixed. Araucarias, Cordylines, Cyperus, Ferns, &c., are especially useful for the purpose. Small groups of dwarf plants are frequently more effective than when the same are distributed as single specimens. The side stages should be about 3ft. above the ground, and, if any of the plants are very dwarf, they should be raised on pots or suspended from the roof.

Climbers and Pillar Plants. These are important and attractive additions to Greenhouse embellishment. Many are, however, rather unusually susceptible to the attacks of insects, and, if the latter are allowed a footing, considerable injury is caused to plants underneath. If taken down from the wires each winter, thoroughly washed, and occasionally examined and sponged afterwards during summer, the majority of climbers may be kept tolerably clean; but, if this is neglected, the plants soon become an eyesore, and fail to succeed. Climbers should be planted out so soon as they are large enough to establish themselves, but good specimens should first be prepared in pots. They have, of necessity, to be placed near the side walls, and, as the hot-water pipes are often there, suitable provision is rarely made for roof-covering plants. If such is the case, they can hardly be expected to grow and flower well. An open compost of sandy peat and loam is best, and any special soil may be placed round particular plants requiring it. Copious supplies of water are necessary in summer, but only a little should be applied during the resting period of winter. One or two wires fixed near each rafter, and the plants limited to covering them separately, is the best arrangement, as exclusion of light from plants underneath must be avoided. Fuchsias are amongst the best of subjects, either for pillars or rafters. Tea and Noisette Roses should always be included, and a light position selected for them. Bougainvillea glabra, Cestrums, Kennedyas, Passifloras, Swainsonas, and Tacsonias, amongst many others, may be planted where there is space for them to develop. Airing and Temperatures. A confined, close atmosphere should always be avoided in a Greenhouse devoted to the general cultivation of plants. Cold draughts and improper airing are equally to be condemned. When proper means of ventilation are provided in span-roofed houses, air may be admitted on the opposite side to that from which the wind blows. In pits, or houses of other shapes, the admission of air is an important matter that can only be practised properly after experience is gained. Young and tender growths are frequently much injured through injudicious airing in spring. During warm summer weather, too much can scarcely be given to plants in flower, but with those making their growth its admission should be carefully regulated. A little ventilation at the apex, especially if the house is closely glazed, is advisable whenever the weather is mild. All Greenhouse shrubs permanently employed, and the majority of spring and summer-flowering subjects, should be allowed to rest during winter, by keeping a rather low temperature and a dry atmosphere. A temperature ranging from 45deg. to 50deg. should be a maximum, and 10deg. less will do no injury. In summer, fire heat should be withheld, and the house kept as cool as possible, for preserving the flowers.

Watering. Although a large proportion of cool-house plants require plenty of water, its application indiscriminately would end in destruction with many others. As a rule, those having the finest roots require the least amount of moisture, and as these are invariably hard-wooded, careful watering becomes one of their special requirements. Rules for watering plants are frequently given, but the knowledge can only be properly obtained by experience. Soft-wooded plants require a much larger amount, as their sappy growths are rarely at rest, and the roots should never be allowed to get too dry.