Very little, if any, pruning or switching should be done till the third year after the fence has been formed, and then only the longer twigs cut back, so as to get by degrees a general uniformity of shape. The switching-knife is alone to be recommended for pruning fences, shears never making a clean cut, and pressing and loosening the bark at the point where amputation took place. A well-sharpened switching-knife in the hands of a dexterous hedger turns out beautiful and commendable work. Unless it be an annual cleaning and trimming, a well-formed hedge should require but little attention for many years. Should it, however, when old, begin to show signs of distress and become gappy, a top-dressing of rich farmyard manure will go a great way towards throwing fresh energy into the plants. This should be applied in winter, and lightly forked in the following spring, and before growth has commenced. Should gaps occur by reason of deaths in the old plants these should be removed, and others of young growth substituted, the soil at the same time being dug out and other fresh from a field or roadside used instead. Great care should be exercised that the roots of living plants are not injured whilst removing the dead and substituting the live specimens. Specially-prepared plants and such as are unusually stout and bushy should alone be used in hedge-repairing. CHAPTER XX SHRUBS FOR SHADY SITUATIONS The list of procumbent or carpeting shrubs that have been found to succeed when planted beneath the shade and drip of forest trees is by no means a long one, and as the clothing of such bare places is often a point of the greatest importance, particularly in park or ornamental grounds, the following notes may prove useful. By careful manipulation much may be done to carpet such places with suitable shrubs, but the task in some instances is by no means an easy one, and must be set about in a common-sense and practical way. Evidently deciduous trees have an advantage over evergreen kinds in that with the extra light and greater amount of surface dampness undergrowth succeeds better beneath their shade. The =common Ivy= is probably the best evergreen carpet for shade planting with which we are acquainted. It runs about and roots freely, soon covering a large space of ground with its neat, deep-green foliage. Propagation is brought about either by means of cuttings or suckers, and is simple and inexpensive. The =Periwinkles= (_Vinca major_ and _V. minor_) are well adapted for planting beneath our larger trees, where, unless the shade is very dense, they succeed admirably, soon forming large breadths of evergreen carpet and producing their deep blue flowers in abundance. They are readily increased by layering or subdivision, and when once established soon spread about unheeded.