Rock Cress.—See "Arabis."
Rocket (Hesperis).—The hardy perennials like a light, rich soil, and need to be frequently divided. The best time to divide them is just after they have done flowering, when they should be potted off, planting them out again in the spring. The annual and biennial kinds merely require to be sown in the open border. Most of the Rockets give forth greater fragrance towards evening. Their flowering season is June. Height, 1 ft. to 1-1/2 ft.
Rock Rose.—See "Cistus" and "Helianthemum."
Rodgersia Podophylla.—A hardy perennial having immense bronze foliage. It thrives best in a moist, peaty soil; flowers from May to July, and may readily be increased either by seed or division. Height, 3 ft.
Rogiera Gratissima.—A pretty evergreen stove shrub, which is often trained to a single stem so as to form a standard. It succeeds in sandy loam and peat. It may be sunk in the flower-border during the height of summer, but must be taken indoors before frost sets in. Cuttings placed in sand under a hand-glass in heat will strike. It flowers in June. Height, 3 ft.
Romneyi Coulteri.—This grand white-flowered Poppy Tree is quite hardy, and will grow in any light, rich soil. It blooms in August and September, and may be increased by seed or by division. Height, 4 ft.
Rose Campion.—A pretty hardy perennial which may be grown from seed sown in autumn, choosing a sheltered site, or in March in a frame or under a hand-glass, transplanting it in the autumn into a light, rich, loamy soil. Height, 2 ft.
Rosemary (Rosmarinus Officinalis).—This hardy evergreen shrub should occupy a dry and sheltered position. Its fragrant purple flowers are produced in February. Cuttings of the ripened wood, if planted in spring, will strike root freely. Height, 2 ft.
Roses.—A good, deep, loamy soil, well drained, but which retains a certain amount of moisture, is the most suitable. The position should be sheltered, yet open and exposed to the sun. The latter part of October or November is the most favourable time for planting, but it may be continued with safety until the commencement of March. A fortnight before planting the holes should be dug out 1-1/2 or 2 ft. deep, and plenty of old manure thrown in and trodden down. On this a good layer of fine mould should be placed, so that the roots do not come in contact with the manure. Great care must be taken not to expose the roots to the cold air. When the ground is quite ready for their reception dip the roots in a pail of water, then spread them out carefully on top of the mould, fill in the earth, and tread it firmly. If the plants are standards they require to be firmly staked. Precaution is necessary not to plant too deeply, keeping them as near as possible at the depth at which they were previously grown, in no case exceeding 1 in. above the mark which the earth has left on the stem. Three weeks after planting tread the earth again round the roots. Pruning should be done in March, except in the case of those planted in spring, when the beginning of April will be early enough. Cut away all of the wood that is unripe, or exhausted and dead. Dwarf growers should be cut back to within two or three buds of the previous year's growth, but five or six eyes may be left on those of stronger growth. The majority of climbing and pillar roses do not require to be cut back, it being only necessary to take out the useless wood. In pruning standards aim at producing an equally balanced head, which object is furthered by cutting to buds pointing outwards. At the first sign of frost the delicate Tea and Noisette Roses need to be protected. In the case of standards a covering of bracken fern or straw must be tied round the heads; dwarfs should have the soil drawn up over the crowns, or they may be loosely covered by straw. Apply a top-dressing of farm-yard manure to the beds before the frosts set in, as this will both nourish and protect the roots. Fork it in carefully in the spring. Cow manure is especially valuable for Tea Roses. After the first year of planting most of the artificial manures may, if preferred, be used; but nothing is better than farmyard stuff. If the summer be dry, water freely in the evening. Roses may be propagated by cuttings in the summer or autumn. The slips should be 5 or 6 in. long, of the spring's growth, taken with 1 in. of the previous year's wood attached. A little bottom-heat is beneficial. They may also be increased by grafting or by separating the suckers. Keep a sharp look-out for maggots in the spring, which will generally be found where the leaves are curled up. These must be destroyed by hand-picking. Green fly can be eradicated with tobacco wash. Mildew may be cured by sprinkling the leaves with sulphur while dew is on them.
Rose of Heaven.—See "Viscaria Coeli Rosa."