The lawn hedge on the border or beside a walk must show uniformity of outline and thickness of base. The only durable forms are those with broad base and an approach to conical form, as shown in Pigs. 60 and 61. The ornamental hedge with perpendicular sides is a failure in a few years. Even in California, where privet hedges were usually trained as shown in Fig. 62 a few years ago are now disfigured by dead patches. With plants of the habit of growth of privet, if needed strength of root is secured, they must be planted twenty inches apart, and as a start for securing a low base the plants must be cut off when planted to stubs only six inches in height. The first growth must be largely lateral as a foundation to build on. Each year thereafter the top can be raised, with sheared sides, until the required height is reached.
Figures 60 and 61 give correct form of hedge. Figure 62 will not give favorable results.
With such evergreens as white spruce and hemlock this severe cutting back at first cannot be practised. But by using plants not more than ten inches in height the lateral growth for a base can soon be secured by pinching or slight clipping of the up-growing points.
The main pruning should be done in the dormant period, but the lighter summer clipping of deciduous plants and the pinching or light clipping of the conifers, must also be kept up while the hedge is forming and after its final height and width have been reached.
In planting for ornamental screens plants can be used with a natural thick base, such as lilac, caragana, and Amur barberry. With slight pruning at top and sides these can be kept in neat form, while heavy pruning would take off most of the flowering and fruiting wood.