This section is from the book "The Gardener V1", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
Any one interested in city gardening (and it is a matter that is often treated of in the horticultural press) can find much to excite their admiration at the present time in what is being carried out along the line of the Thames Embankment, on the north bank of the noble stream that flows through the great metropolis. From Blackfriars to Westminster bridges there now runs a line of magnificent roadway, of considerable width and admirably constructed, which has been designated the finest thoroughfare in Europe. This roadway is placed along by the river, with a broad pavement for foot-passengers on either side of it, and by the edge of this pavement nearest to the roadway, on both sides, runs a line of fine young plants of the Occidental Plane (Platanus occidentalis) for a considerable distance. These were planted two years ago, and with very few exceptions they have succeeded well, and are now growing into nice trees with well-furnished heads. All these plants, averaging from 16 to 18 feet in height, were obtained from the Continent for the purpose; and during the present winter the remainder of the thoroughfare will be planted in a similar manner. Already 250 trees have been placed there, and another 150 trees will complete the remaining distance.
The trees are planted 20 feet apart, and it is expected that in ten years' time each alternate tree will be removed, so as to allow space for the remainder to develop themselves. To receive the rest of the trees intended to remain permanently, pits have been dug, 9 feet square and 6 feet in depth; these are filled in with 1 foot of brick-rubble for drainage, and then with a rich loam obtained from land belonging to the Metropolitan Board of Works at Barking Creek; for it is under the auspices of this important public body that this great improvement is being worked out. The pits to take the trees which it is calculated will be removed eventually are of less dimensions, being 6 feet square by 4 1/2 feet in depth. After each tree is planted, a square iron grating in four divisions is placed round each tree on a level with the pavement, so constructed that water can be poured into the roots of the trees when requisite, without any necessity for the removal of the grating. Round each tree has hitherto been placed an iron girdle about 6 feet in height; but as the trees, in the event of a high wind, are apt to sway about and snap just at the collar of the girdle, three stout upright pieces of deal about 10 feet in height are being substituted for the girdles, and serve to keep the trees much more secure.
Between this fine thoroughfare, with its lines of Plane-trees, now universally acknowledged to be the best of all trees for European cities, and the line of warehouses, dwelling-houses, etc, skirting what was once the river's edge, there is an immense piece of reclaimed land, a good portion of which is being formed into public gardens. To fill up this reclaimed space thousands of loads of soil were required; happily with the progress of the Thames Embankment came the construction of the subterranean way of the Metropolitan District Railway, running close by and parallel with the thoroughfare, and this gave ample material to form the subsoil. Then, to give a suitable top-soil, immense quantities of loam were brought up by water from Barking Creek, well adapted for the growth of shrubs, and nearly the whole of the space to be planted with these is now ready for their reception. Along that portion of the land to be so planted that skirts the old line of the river-side, a sloping bank, rising in some instances 9 or 10 feet, has been formed, with a broad verge of grass towards the river. There is also a similar verge of grass, with borders for shrubs at intervals, along by the promenade; and between the verges runs a broad concrete walk, solid and firm as a rock.
The borders will be filled mainly with deciduous mingled with such evergreen shrubs as will thrive best on such a spot, amid the city's smoke and dust. Hollies, both plain-leaved and variegated, Euonymus of kinds, Aucuba japonica, and a few others, will form the evergreen shrubs; and about the grass will be dotted specimen Hollies, etc, likely to prosper there. Between the walk and the grass, on both sides of the former, there runs a verge of Irish Ivy rather more than a foot in width; this has been somewhat thickly planted, and pegged down on a surface covered with 2 inches of well-rotted manure; and already it is rapidly taking root, and by the middle of the summer it will be a mass of green leaves marbled with a darker hue.
The construction of the concrete paths well deserves a record. A foundation of about a foot in depth is laid of rough bricks, with some gravelly soil thrown over to make it level. On this is laid 4 inches of concrete, which, when it settles down and is well rolled, becomes as hard and firm as a stone pavement. The concrete is formed* of gravel well saturated with tar. The gravel is thoroughly heated over a fire, and while hot sifted into two sizes, and the tar mixed with it. A layer of 2 inches of the coarse gravel, covered with a layer of the fine gravel of a similar thickness, forms the surface of the path, and over it is thrown a thin layer of powdered shells or fine shingle from the sea-shore at Brighton; the latter is to be preferred, as the wind is apt to lift the former and scatter it over the turf. This path may perhaps yield slightly on a very hot sunny day, but only in a small degree.
From the roadway the gardens will be separated by means of a handsome iron fence, through which, at certain places, the public wi]l gain access to the gardens by means of gates.
The most elaborate plot of garden will be that at the east end of Somerset House and near the Temple Gardens. Here a large fountain is being constructed; and round about and near it there "will be several beds for flowers and foliaged plants during the summer months. To this spot can come hundreds of pent-up citizens and indoor workers during the temporary respite from labour at mid-day, and in the evening, after their toil is ended, to wander along pleasant paths and round about gay flowers, on a spot that was but a few years ago a portion of the bed of the great river that flows through the city. Truly it is a wonderful transformation-scene; and it is only those who knew the river-side ere the embankment was commenced that can comprehend the splendid improvement effected which gives a broad line of thoroughfare from the new bridge at Blackfriars to that at Westminster, ornamented by fine trees, with a smiling garden on one side and the flowing river on the other.
The laying-out of the garden and shrubbery-grounds has been carried out by Mr Joseph F. Meston, under the superintendence of Mr Alexander M'Kenzie; and Scotland has reason to be proud of the achievements of her two worthy sons. R. D.