All the ground not covered by trees or shrubs I have directed to be laid down in grass to be kept closely mown; but round each tree and shrub forming the collection I have preserved a circular space, varying from 3 ft. to 5 ft. in diameter, which (with the hill in the centre, comprising one third of the width of the circle, and on which the plant is placed) is not sown with grass, but is always to be kept clear of weeds. The use of this circle and little hill is to prevent the grass from injuring the roots of the trees while young, and to admit of the larger roots showing themselves above the surface, where they ramify from the stem, as before mentioned. Some few of the shrubs which require peat soil, such as the heaths, have had that soil prepared for them; and the genera Cistus and Helianthemum, which are apt to damp off on a wet surface, are planted on a raised mass of dry rubbish, covered with stones, as shown at 40. in the plan fig. 52. p. 522. All the climbing plants throughout the collection have iron rods, with expanded umbrella-like tops, placed beside them; the lower end of the iron rod being leaded into a block of stone, and the stone set in mortar on brickwork, so that the upper surface of the stone appears 1 in. higher than the surrounding surface. This appearance of the stone above the surface is not only more architectural and artistical, but better adapted for the preservation of the iron at the point of its junction with the stone, than if the stone were buried in the soil.
