Be sure to house before the faintest suspicion of frost, as this sun-lover is extremely tender, and the slightest nipping harms it. Give it a southern exposure in your room, and place close to the glass; and if you have not a double window, leave the fly-screen in to save the leaves and blossoms from immediate contact with frosty panes. A heliotrope should never once become wholly dry, and should have a weekly drink of manure-water, which must be about the color of moderately strong coffee. For insect pests, dust the leaves with a light feather-brush, and then wash thoroughly. This process must be repeated as often as the insects appear.
The odorous sacred lily of China we all, no doubt, grow yearly in water, with a bottom layer or two of pebbles. It is well to make incisions lengthwise of the bulb with a sharp knife before planting, and there should be lumps of charcoal among the pebbles to keep the water sweet. A single bulb, thus treated, will give one seven flower-stalks. The old-fashioned plant, the calla, though less common than it was twenty years ago, if grown in an artistic vase and given an entire window, is beautiful.
It has been said of the calla that "it needs water like a mill, heat like a furnace, food like an army, and absolute rest during the summer." "Keep its feet in water," says the florist. In its native habitat it is in water to the depth of a foot or more, in broad open sunlight, and in soil as rich as decayed vegetation can make it. Soon after flowering season the water subsides, and the soil becomes as dry as it is possible to get in the tropics. Here, nature teaches us how to cultivate the calla. The canna thrives admirably as a house plant, and has a happy way of accommodating itself to circumstances, which makes it especially desirable for decorative effect. In a sunny window it will flower all winter if given abundant heat. In a north window of the same room it will give one beautiful foliage, and it will, "at a pinch," take a back seat and hold its own in the shade, grouped with the statuary and screens, where, with its large, handsome leaves, it will impart to the drawing-room a certain air of oriental languor and magnificence. The canna should be lifted early in September and placed in rich loam, in a large, well-shaped pot or vase, and kept for a week or two in the open, in partial shade, and well watered. It must be carefully housed before the lightest frost appears. Its vigor and beauty are increased by the addition of wood soot to the soil.