CHAPTER XXI.
HARDY PLANTS IN THE GREENHOUSE.
Incidentally several kinds of hardy plants have been referred to as suitable for greenhouse cultivation. It remains, however, to be said that there are certain kinds of hardy herbaceous and alpine plants that really require the shelter of glass, but never need the aid of artificial heat, and are particularly worthy of the attention of the amateur who can find delight in seeking out the minor gems and jewels of the vegetable kingdom. There are to be found hundreds of plants of the most beautiful character and the most hardy constitution, which it is difficult to keep alive in the open border, not because our winters are too cold, but because they are too damp and variable. Many of these are known as “frame plants,” and others are grown on rockeries, and others again are popular bedders, and a considerable number are varieties that puzzle their possessors until they are taken into an unheated airy greenhouse, and there they thrive in a surprising manner. We propose that a selection of such plants should be made expressly for cultivation under glass, and to present the idea in the simplest manner possible we will build for them a low span-roofed house, with sliding lights and glass sides, resting on low brick walls: in these walls ventilating shutters; the inside furniture to consist of a simple stage on each side, and that is all. The question of heating is intentionally avoided, for this house is not to be heated for (amongst many) three good reasons. In the first place, heating, no matter by what means, occasions much expense and trouble, and unless there are regular gardeners employed, it usually proves a vexation beyond its value, and the neglect of one night may result in the loss of a whole houseful of plants, when perhaps the winter is nearly over. In the second place, for the plants to be grown in this house, fire-heat is not
