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should be diligently cut away as soon as they appear, otherwise they injure the effect of the foliage. Propagate in the same way as the preceding. There are many finer plants in the same colour of variegation for massing and edging; but it makes a pleasing variety in the front lines of mixed borders of hardy perennials.
Cardamine (Bitter-Cress).—This is a large genus, yielding, however, very few species of much value for embellishment. They are plants of easy cultivation, succeeding very fairly in most soils and situations if not dry in the extreme, but are best adapted for moist or even marshy places. Propagate by seed in March or April in the open ground, or by division any time
C. pratensis flore-pleno Double-flowered Bitter-Cress). This is a very pretty pleasing plant, with little that is showy about it, but no little grace. The simple-flowered form is rather a common plant in moist places in Britain generally, but the double variety is not met with in nature, and not often even in cultivation. It is a pretty ornament of rockwork or moist borders. The leaves are pinnate, pale green; the flower-stems rise to the height of about 9 inches, bearing numerous flowers in open trusses. The flowers are pale pinkish purple, or white tinged with that colour, and are rather large, appearing in April and continuing far into summer.
C. trifolia (Trifoliate-leaved Bitter-Cress).—This is a pretty species with white flowers from Switzerland. It forms rather flat tufts of dark green, almost shining smooth trifoliate leaves, from the axils of which spring the simple leafless flower-stalks, supporting a somewhat dense truss of flowers, rather smaller in size than those of the preceding. They are very pure white, and appear in March and April. Height about 9 inches or i foot, suitable for culture in drier soils than the preceding sort.
Cheiranthus (Wallflower).—There is about an equal number of hardy and half-hardy species comprised in this genus. The latter must be passed over here with the remark, that most of them may be cultivated in the neighbourhood of London, and in the counties beyond it southward and westward, but generally not farther north, except in the mildest seasons. The best are C. mutabilis from Madeira, growing about 3 feet high, and producing a profusion of pale-yellow and purple flowers in April and May. C. mutabilis var. longifolius, commonly in catalogues named C. longifolius, has longer and narrower leaves, and pale pinkish-purple flowers faintly tinged with white, but in other respects is the same as the species. C. semperflorens, from Barbary, grows about 2 feet high, with white flowers,
which in the greenhouse appear at all times; and out of doors, where favourably situated, as against a wall in a warm aspect, a very long and continuous succession of bloom is kept up. Among the hardy species, however, the most showy and useful are to be found. The common Wallflower may be taken as the type of the family as regards the form of the flowers; but some of the dwarf species are superior to the best varieties of it in point of compact neatness of growth, while they are in no wise inferior as regards showy qualities and the duration of the blooming period. All Wallflowers delight in rich warm light soil, but they succeed very fairly in almost any soil. The varieties of common Wallflower are propagated by seed sown in the open ground from March till July, at several periods, for the purpose of keeping up a long succession. In mild seasons the plants from March sowings bloom throughout the winter, and later sowings succeed them in their order, carrying the display far through the summer. The double varieties of C. Cheiri are best propagated by cuttings, and so also are the other species. They are all rather short-lived perennials, both the tender and hardy species; it is necessary, therefore, to anticipate debility by keeping always a few young plants in stock either from seed or cuttings. The cuttings may be struck out of doors in sandy soil under a hand or bell glass, in a place where they may be shaded from the mid-day sun, and they are most easily struck when the fresh growth is just beginning to harden at the base.
O. alpinus (Alpine Wallflower).—This species grows from 6 to 9 inches high, producing dense masses of bright yellow flowers from April till July. It is admirably adapted for the embellishment of rockwork, the front lines of hardy mixed borders, and for spring massing in the flower-garden. It succeeds very well in shady places, as among shrubs and on banks with a north aspect.
C. Cheiri (Common Wallflower).—This is too familiar a plant to require description. It has been a cherished garden-plant for centuries; and on account of its showy flowers and rich perfume, it will no doubt ever remain a favourite with all lovers of sweet and beautiful flowers. There are a good many varieties, both single and double, which may be procured in separate colours or in mixture; but certain of the double varieties can only be kept up true to kind by means of cuttings. The double yellow, double variegated, or yellow and red, the C. C. var. patulus or double-spreading, and the double blood-flowered or C. C. hæmanthus, are all sorts that, if valued, must be kept in stock by cuttings, as they rarely seed; and even if they do,
it cannot always be depended on that the progeny will be the same as the parent. The value of Wallflower for embellishment can scarcely be too highly rated; and as it is very generally appreciated, there is no great need for insisting on it; but there is a purpose for which it is admirably adapted that cannot be too strongly urged, especially as it is only very rarely seen used for it, and that is the decoration of ruins or old walls and rocky banks, where little else having much claim to be considered bright and beautiful will live, far less embellish. The single varieties may be established in such places at very trifling cost and trouble. The merest film of soil, if hard and firm, will support the plants for years. They may be sown where it is desired they should be established ; and when they do take hold, they will sow themselves and spread in all directions. C. Marshallii (Marshall's Wallflower).
This is one of the handsomest, if not the most handsome and showy, of the group. It is said to be of hybrid origin, the alleged parents being C. alpinus and C. Cheiri; but it inherits the characteristics of the former only to any degree, and no one would suspect that it was a blood relation of the latter by a comparison of their respective features. It is rather more robust in habit than C. alpinus, and the trusses of flower are somewhat larger, but it is a most compact plant, growing from 9 inches to 1 foot high, and producing an immense profusion of bright orange-coloured delicately - scented blossoms. It is a brilliant ornament of rockwork and the mixed perennial border, and a choice subject for massing or edging use in spring bedding-out; few plants indeed, so hardy and easy to cultivate, equal it in showy beauty and continuance of massy display. Every amateur and cottager should grow a plant or two of it. Flowers from April till July.
C. ochroleucus (Straw-coloured Wailflower.)-This species resembles the last in habit and stature, and form of leaves, but the flowers are lemon or straw coloured. It is a profuseblooming plant, producing its flowers in April, May, June, and July. Height from 9 to 12 inches. Native of Switzerland.
Diptolaxis tenuifolia syns. Brassica tenuifolia and Sisymbrium tenuifolium-is a member of an uninteresting genus, and though flowering the summer throughout, would not be tolerated in flower-gardens in its normal state of weediness; but a variety with variegated leaves is well worth cultivating where variegated plants are in request, as it is tolerably handsome if well managed. The leaves form considerable tufts about 9 inches high, and are 5 or 6 inches long, pinnate or pinnatifid, but often also simple or undivided except by a few irregular shallow notches per
fectly smooth, and margined with creamy yellow. It is not one of the most elegant of hardy variegated plants, but is very distinct, and has the additional merit of being adapted to grow in dry sandy soils where many of the more choice variegated kinds would not exist ; indeed it should be planted in poor soil in order to insure the best development of its peculiarities, being apt to run green in rich soil. Native of Britain. The flower-stems should be diligently removed as soon as they appear.
Draba (Whitlow-Grass).—A rather numerous genus, comprising both annual and perennial plants, but mostly perennial. They are diminutive alpine plants inhabiting the most elevated positions in the lofty mountain-ranges of both hemispheres and the arctic regions. They are best adapted, therefore, for culture on rockwork, on which they are very pretty ornaments, though, like most of the inhabitants of those wild and frigid homes, they are difficult to keep under the more genial influences of our climate. They are propagated by seeds sown as soon as ripe in a cold frame, or under a hand-glass in small potsor the seed may be kept over winter, and sown in March in the same way; and in each case they should be pricked off into gritty loam, two or three together in a small pot, well drained, keeping close and shading for a few days till the plants begin to grow. They may also be increased by cuttings in spring, after some growth has been formed, in sandy loam under a glass out of doors in a shady place ; and by division in spring as growth commences, or in autumn after growth is quite matured. Gritty moderately-rich loam is the most congenial soil to these plants, and they prefer a rather sunny position.
D. aizoides (Aizoon-like D.)- This is a dwarf-tufted species growing about 3 or 4 inches high, producing its narrow rigid leaves in densely-packed, somewhat pyramidal, rosettes. The flowers are bright yellow, in small compact trusses, and appear in March, April
, and May. Native of the mountains of central and southern Europe; found also indigenous in Wales, but suspected of having strayed from cultivation to the natural positions it inhabits near Swansea.
D. Aizoon (Aizoon D.)—This species is nearly related to the last, but distinct. The habit of growth and foliage are similar, but the flowers are smaller, in larger clusters, and are pale yellow or sulphur; they appear at the same time. Height 3 to 4 inches. Native of Carinthia.
D. ciliaris.—This species is very distinct in foliage and flowers from either of the preceding. It grows about the same height, but the foliage is less rigid both as regards texture and
arrangement. The flowers appear in March, April, and May, are pure white, large individually as compared with those of the preceding, in loose clusters. Native of Switzerland.
Hesperis (Dame's Violet or Rocket).—This is not a numerous genus in perennial species, but is of great value, on account of a few varieties of the common Rocket H. matronalis, the great beauty of which is much enhanced by the delicious fragrance they possess. The single varieties of Rockets are tolerable as components of the mixed border only in large collections of perennials : their proper use and value, however, is in the ornamentation of open woods, banks about streams and lakes, semiwild places either in partial shade or sunshine, and shrubberies. Their ornamental qualities are not of the highest character, but their fragrance is welcome everywhere. The double varieties are much more ornamental, and they produce a more permanent floral effect, while their fragrance is not inferior to that of the single ones. They are fit to grace the most select position, and they are especially commendable to amateurs,whose gardens, being limited, should contain only the cream of gay plants and sweet. One drawback to their being universally cultivated must be noticed. They are very short-lived in many soils, especially those of a light sandy texture. It is often experienced that, while the single varieties grow and flower well in such soils in a state of nature—that is, with the surrounding surface clothed with herbage—the double sorts become quickly unhealthy, and will not be coaxed to live for any length of time under the conditions of cultivation or artificial keeping. In and about large towns, except the soil is very congenial, they rarely succeed well, as they have a special repugnance to the smoky impure atmosphere of towns and their environs. The soil in which they attain their greatest luxuriance and beauty is a rich deep loam, well drained, on a cool bottom. But under the most liberal treatment, and in the most suitable soil, they are apt in a few years to decline in vigour and ultimately die out. The species is, in fact, but a rather long-lived biennial, and it is consequently necessary to propagate periodically by cuttings in order to keep up a healthy vigorous stock of flowering plants. Cuttings may be taken at various periods and in different conditions: when they have made a little growth in spring; when, after early flowering, the stems have been cut down and second growth made; and just when the flowers are on the wane the stems may be cut over and used as cuttings. To take cuttings at the first period entails of course a greater or less loss of flower; but it sometimes happens that the choice lies between that temporarily and the total loss of stock; and if the