Commelina Sellowina (Blue Spider Wort, or Day Flower).—A pretty greenhouse climber, bearing cobalt-blue flowers. It should occupy a sunny position, and be watered freely from March to September, after which very little should be given.
Commelina Tuberosa.—Perfectly hardy plants, bearing in June blue or white flowers the size of a shilling. The bulbs may be planted in spring in any garden soil; the plants are increased by off-sets. Height, 1-1/2 ft.
Compost Heap.—Get a heap of dead leaves and press and jam them down as closely as possible. Then take as much manure, in appearance, as you have dead leaves, and for each cartload have two bushels of unslaked quicklime and some earth. Now spread upon the ground, in some out-of-the-way corner, a layer of the dead leaves, upon which sprinkle a layer of lime, and over that a thin layer of earth. Next lay on a covering of manure, then a layer of leaves, and one of lime and earth as before, and proceed in this way till all the materials are used up. It will be well, however, to give the heap a good watering whenever you come to the layer of leaves. This slakes the lime and hastens the decomposition of the vegetable matter. After letting it stand for about six weeks, begin at the top of the heap and turn it completely over, so that what was at the bottom will be at the top. Repeat this operation from time to time at intervals of six or seven weeks, until it has become perfectly friable and will powder through a garden-fork like dust. It will then be ready for use. This compost is invigorating to flowers of all kinds, and is so ready for them to assimilate.
Comptonia Asplenifolia.—This ornamental deciduous shrub is quite hardy, but requires a light, sandy loam or peat soil and a shady situation. It is increased by layers. Blooms in April. Height, 4 ft.
Cone Flower.—See "Echinacea."
Conifers.—Conifers (so called because they bear cones in place of ordinary seed) are mostly of tall growth, yet among the class are many low—growing evergreens well adapted for the lawn or border. Indeed, any of the specimens may be utilised in this way, but of course must be removed from the shrubbery or border before they attain undue proportions. They are hardy, and, generally speaking, not particular as to soil or situation. Firs, Pines, Cedars, etc., come under this heading, and mention is made in other parts of this work of those most suitable for the amateur's requirements.
Convallaria Prolificans.—This is one of the most beautiful hardy perennials known. It has large, deep-green foliage, with erect and much-branched flower-stems. The flowers are white, internally flushed rose; are very fragrant, and are produced from May to September. The plant will grow in any ordinary soil, and may be increased by dividing the root. Height, 2-1/2 ft.
Convolvulus (Morning Glory).—Showy plants. The tender species are well adapted for the stove or conservatory, and are best grown in loam and peat: cuttings strike freely in sand under a glass. The half-hardy annual kinds should be sown on a gentle hotbed in February, and when large enough transferred to the open; or they may be sown in the open in April. Hardy kinds merely require sowing in the open, early in spring. The stove and greenhouse annuals and biennials require to be sown in heat, and treated as other stove and greenhouse annuals and biennials. Flowering season, May to July. Height, 6 in. to 15 ft.
Coral Plant.—See "Erythrina."
Corchorus.—See "Kerria."