Clematis (Virgin's Bower).—These plants like a dry situation. They will grow in smoky districts, and may be increased by cuttings of firm side-shoots under a glass in summer or by layers in September. With the protection of a greenhouse they come into flower early in spring. They are the most beautiful of all flowering hardy climbers. The stove and greenhouse varieties are best planted in loam and peat, though they will thrive in any light soil. Any good garden soil suits the hardy kinds. The herbaceous varieties are increased by dividing the roots early in spring. They bloom at various periods. After they have ceased to flower, the Jackmanni and Viticella sections should be cut down to within 9 or 12 in. of the ground. The Patens and Florida do not require pruning; those of the Lanuginosa should be cut back moderately, but not too close. A good dressing of leaf-mould and manure should be dug in about November. Heights vary from 2 ft. to 20 ft. (See also "Traveller's Joy.")
Cleome.—The species of this genus are very pretty and free flowering, some being half-hardy climbers notable for their foliage. They like a rich, light soil. Cuttings of the stove kinds root freely under a glass. Some of the annual species require to be sown in a hotbed frame or in a hot-house, then potted off and placed with tender annuals. The hardier ones may be sown on a hotbed, and afterwards planted out in a sheltered position. They flower in May, June, and July. Heights vary from 6 in. to 8 ft.
Clethra Alnifolia.—This hardy deciduous shrub bears in September deliciously scented pure white flowers on the side-shoots of the previous year's growth. It needs a light soil and a dry, sunny situation. It may be propagated by cuttings placed under glass in sandy loam, or by suckers taken when the leaves have fallen, but is more generally increased by layers. Height, 3 ft.
Clianthus.—A genus of very elegant, free-flowering, evergreen greenhouse shrubs. They flourish in the border of the conservatory (or against a south wall if protected from cold) in an equal mixture of loam, peat, and sand. Cuttings root freely in the same soil under glass. Seed sown early in spring produce flowers the first year, in May. Height, 3 ft. to 4 ft.
Clintonia.—Very pretty half-hardy annuals; useful for beds, edging, pots, or rock-work. They produce an abundance of Lobelia-like flowers in August. Sow the seed in the open in spring. Height, 6 in.
Clitoria.—A greenhouse climbing or trailing plant, which thrives in a mixture of loam, peat, and sand. Cuttings will strike in heat, but it is more readily grown from seed.
Clivias (Caffre Lilies).—Most beautiful evergreen plants for the greenhouse. The soil most suitable for them is a compost of leaf-mould, loam, and sand. Give a liberal supply of water when in full growth, but from September to February keep them only moderately moist. Shade from strong sunshine, and keep the temperature at from 60 to 70 degrees. They will not bear much disturbance. Seed may be sown in bottom-heat early in spring, or they may be increased by suckers.
Cobæa Scandens.—This rapid climber is well adapted for the conservatory, but it will thrive in the open air if the root is protected during the winter. If planted against a rough wall its tendrils will catch in the crevices and support it without any assistance. It requires plenty of room and a rather poor soil, otherwise it runs to leaf instead of to bloom. The tops of the shoots should be constantly pinched off, to induce thickness of growth. Cuttings of firm side-shoots taken in summer will root under glass in a little moist heat; but it is best raised from seed, sown sideways, in a hotbed in March. Its blue and purple flowers are produced in August. Height, 10 ft. to 20 ft.
Cob Nuts.—See "Filberts."
Cockscomb.—These tender annuals should be sown on a moderate hotbed in March or April, in pans of leaf-mould and sand, covering with 1/4 in. of soil. When a couple of inches high place them in small pots, replace them on the hotbed, and give shade till they have taken fresh root. When the weather is favourable let them have a moderate amount of fresh air. Afterwards shift them into larger pots, and when the combs are full grown place them in the greenhouse, taking care not to allow any damp to lodge on them, at the same time supplying them well with water and all the air possible. Height, 9 in. (See also "Celosia.")