Part 38

Rhubarb, Chilian.--See "Gunnera."

Rhus (Sumach).--Lovely shrubs, growing in any ordinary soil. The young shoots of R. Cotinus are clothed with round leaves which change to bright crimson and orange, surmounted with fluffy pink seed-vessels, while R. Glabra Laciniata resembles a tree fern. They may be propagated either by layers or cuttings. Height, 8 ft. to 10 ft.

Rhynchospermum (Trachelospermum) Jasminoides.--A pretty, evergreen, woody climber for the conservatory, which succeeds best in a compost of light loam and peat; is of easy culture, and readily increased by cuttings. It is a fine plant for rafters or trellis, and produces in July deliciously fragrant white flowers at the ends of the branches. Height, 10 ft.

Ribes (Flowering Currants).--Well-known shrubs, growing in any soil, and flowering early in spring. The colours vary from crimson to white. They may be raised from cuttings either in autumn or early spring. Height, 4 ft.

Richardia Aethiopica.--A fine herbaceous perennial with very bold leaves. It needs a good supply of water, and on dry soils should be planted in trenches. A light, rich mould is best for it, and it should have sufficient sun to ripen the wood. Lift it in September and winter in the greenhouse. It is increased from off-sets from the root, and flowers in March. Height, 2 ft.

Ricinus, or Palma Christi (Castor-oil Plant, etc.).--The foliage of these half-hardy annuals is very ornamental. The plants like a rich soil. Sow the seed early in spring in a slight heat, harden off gradually, and put out at the end of May in a warm, sheltered spot. They may also be propagated by cuttings. Height, 3 ft. to 6 ft.

Robinia.--All these shrubs have fine, Fern-like foliage which changes colour in autumn. The Pea-shaped flowers vary in colour from cream to purple, and while in bloom the plants are very handsome. They grow in any soil, flower in May and onwards, and are increased by layers. Height varies, the Rose Acacia (Hispida) reaching 10 ft., while the Locust Tree (Pseudo-Acacia) grows to the height of 40 ft.

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."

Rose of Sharon.--See "Hibiscus Syriacus."

Rubus.--See "Blackberries."

Rudbeckia (Cone Flower.)--Hardy annuals yielding yellow flowers in July. They are readily grown from seed sown early in spring, and will grow in any garden soil, but naturally succeed best in deeply-worked, well-manured ground. They may be increased by division in October or November, as well as in spring-time. Height, 3 ft.

Ruscus Aculeatus (Butchers Broom).--A hardy evergreen shrub which thrives in any rich soil, and may be increased by division of the root. Height, 1 ft.

Ruta Graveolens.--This hardy evergreen shrub is a species of Rue. It enjoys a good, rich soil, in which it flowers freely in August. Cuttings may be struck under a hand-glass. Height, 3 ft.

Ruta Patavina (Rue of Padua).--For rock-work this hardy perennial is very useful. It likes a dry yet rich and light soil. At midsummer it produces an abundance of greenish-yellow flowers. It can be raised from seed, or cuttings may be struck under a hand-glass. Height, 6 in.

Saffron, Spring.--See "Bulbocodium."

Sage.--This useful herb likes a rich, light soil, and is propagated by division of the root, by cuttings, or by seed.

Saintpaulia Ionantha.--The leaves of this plant spread themselves laterally just over the soil, forming a rosette, in the centre of which spring up large violet-like flowers. It is a continuous bloomer. A rather light, rich soil or vegetable mould suits it best. The seed, which is very minute, should be sown early in spring, in gentle heat: to prevent it being washed away, the pots may stand up to the rims in water for a while when the ground wants moisture. Height, 1 ft.

St. John's Wort.--See "Hypericum."

Salix Reticulata.--A dwarf creeping plant whose dark green leaves eminently fit it for the rock-work or carpet bedding. It will grow in any soil, but prefers a moist one, and produces unattractive brown flowers in September. Propagated in spring by detaching rooted portions from the parent plant and planting them in moist, sandy loam. Height, 2 in.