It may here be observed, that for all border plants, as well as for tulips, ranunculuses, and other flowers kept in beds, the earth or the compost should not be screened fine. It is enough, if stones which the spade sensibly strikes against be cast out, and if clods be broken small at the time of delving. Screened earth is apt to bind after heavy and continued rains, and thus to impede the progress of the roots which it was meant to facilitate. For plants kept in pots, and particularly for seedlings and cuttings, the matter is quite otherwise ; the soil for most of these should be made fine by passing it through a sieve.
Edgings.
463 In the formal style of gardening which prevailed in the 17th and the early part of the 18th century, edgings of various kinds were much more needed and more attended to than they now are. The compartments of parterres were generally divided by box, and on the margins of the walks were frequently small hedges of lavender, or rue. Thyme, savory and hyssop, were also in those days employed as ornamental edgings.
464. For the general gravel-walks in gardens, the best edging is without doubt the dwarfish Dutch box (Buxus sempervirens vat.) A compact low hedge of this effec tually keeps the walks clean, by preventing the earth of the border feom falling down into them, or being washed into them by heavy rains. If the box be kept low and re gularly clipped, it endures in good repair and beauty for several years. It is commonly clipped twice in the year, in April and July. It should be kept about three inches broad at the base, and tapering upwards to a sharp ridge. A linear and continuous edging of this kind pleases every eye. Box is planted either in the beginning of autumn, or in the spring about the mouth of April. If slips having few or no roots be used, watering is proper till the plants be fairly established.
Next to box, t'he plant which forms the best retaining edging is perhaps thrift or sea-pink (Starke arnzeria.) In June and July, when in flower, it makes a showy edg ing ; and it answers the purpose during the rest of the year with its dense tufts of leaves. It should be replanted every year, or at farthest every second year.
The double-flowered daisy (Bcllis perennis, var. fl. pl.) has very long been used in this way. When kept in repair, it forms an edging very pleasing to the eye. The plants should be separated and transplanted every season, in the beginning of September, and only one strong stem or bud left to each bunch of roots.
Double catclOy (Lychnis viscaria, fl. pl.) is sometimes employed; but it seldom makes a neat edging : the flowers are ornamental, but the stems are too tall. Dwarf gentian (Gentiana acaulis) of all other plants forms tue utmost bril liant edging, while in flower in the spring ; but it is neces sary that a continuous azure line be kept up, and for this purpose the verge must be of some breadth : It is appli cable therefore only to large or broad borders, and it suc ceeds best in a strong or clayey soil. London-pride (Saxi fraga umbrosa) forms a loose and straggling verge, but is very pretty while the plants are in flower : It is fittest for a shrubbery walk. Lady's cushion, or Indian moss as it is sometimes called, (Saxifraga hypnoides) is occasionally planted as an edging, and makes a pretty enough appear ance. Some other similar species of Saxifraga, such as palmata and cespitosa, may be used in the same way.
For gay parterres, the large blue-flowered pansy violet (Viola tricolor var.) makes a beautiful slight edging. Al though strictly speaking, an annual plant, if it be parted every season, it endures for several years. It is very com monly used for adorning the margins of elegant flower-bor ders in the neighbourhood of Dublin.
Dwarf bell-flower (Campanula pumila, or C. rotundi folia var.) makes a fine edging for little borders where nice ty and beauty are studied. Sometimes a few feet of the edging are formed alternately of the blue and of the white variety. For small borders, also, a very ornamental edg ing may be formed of Stone crop (Sedum acre), preferring the variety which has the tops of the shoots of a yellowish colour; this, even during winter or very early in the spring, having the appearance of being in flower.
It may be remarked, that patches of several of the differ ent edging plants which have been enumerated, perhaps a few yards alternately of each, have an agreeable effect, es pecially in a long or extensive border.
Most kinds of edgings may be planted early in the spring. In planting them, it is more proper to use the spade than the dibble. The ground being slightly beat, a drill is cut by the garden-line, perpendicular on the side next the border ; the plants are then placed against the perpendicular side, their roots spread out, and the earth closed upon them.