Celery.—­Sow in February or early in March on a mild hotbed for the earliest crop.  Prick the seedlings off into shallow boxes as soon as they are large enough to handle, and keep them rather close and warm until they are established.  Towards the end of March prick them out in rows in a frame, setting them 6 in. apart each way, and early in May transfer to rather shallow trenches, protecting them from night frosts.  For main and late crops sow in a cold frame in April and plant out in June or July, 9 in. apart, in trenches 3 ft. distant from each other, 9 in. wide, and 18 in. deep, pressing the soil firmly round the roots.  Earthing up should be delayed until the plants are nearly full grown, and should be done gradually; but let the whole be completed before the autumn is far advanced.  When preparing the trench plenty of manure should be dug into the soil.  Water liberally until earthed up to ensure crisp, solid hearts, and an occasional application of liquid manure will benefit the plants.  During winter protect from frost with straw, or other suitable material.

Celosia (Feathered Cockscomb).—­Sow the seed in early spring in a warm frame; prick off singly into small pots, and re-pot as they advance in strength in a compost of loam, leaf-mould, old manure, and sand.  Their final shift should be into 24-sized pots.  Give them abundance of liquid manure, never allowing them to become dry, and syringe freely.  These half-hardy annuals, rising to the height of 3 ft. and bearing fine spikes of flowers in July and August, make fine pot-plants for table decoration.  They may be planted in the open, in June, choosing a warm, sheltered situation and rich, loamy soil.

Centaurea.—­The hardy annual and biennial kinds merely require to be sown in the open in the autumn.  The half-hardy ones must be sown on a slight hotbed, where they should remain till strong enough to be planted in the border.  Cuttings of the perennials should be inserted singly in 3-in. pots filled with sandy loam, placed in a shady, cool frame till established, and then watered very carefully.  The different varieties vary from 6 in. to 2 ft. in height, and flower from June to August.

Centauridium Drummondi.—­A blue hardy annual which may be sown in the open in spring.

Centranthus.—­Ornamental hardy annuals.  Sow in the open border in March in any good, well-drained soil.  They flower in June.  Height, 1-1/2 ft.

Cephalaria (Yellow Scabious).—­Strong-growing hardy perennials, suitable for backs of borders.  They succeed in any garden soil, and are propagated by seed or division of root.  Height, 3 ft. to 5-1/2 ft.

Cephalotaxus (Podocarpus Koraiana).—­Handsome conifers of the Yew type.  These shrubs are quite hardy, and in favoured localities will produce berries.  They succeed best in a damp, shady spot, and may be increased by cuttings planted in heavy loam.

Cerastium Biebersteini.—­A hardy trailing perennial which will grow in any light soil, and may be increased by suckers.  It flowers in June.  Height, 6 in.