Prunella Grandiflora.--A pretty hardy perennial, suitable for a front
border or rock-work, bearing dense spikes of flowers from May to
August. It grows well in any ordinary soil, and is propagated by
division. Height, 6 in.
Pruning.--The main objects to bear in mind in Pruning any kind of bush
or tree are to prevent a congested growth of the branches, to remove
any shoots that cross each other, as well as all useless and dead
wood, and to obtain a well-balanced head. It may be done either in
August or in the winter when the sap is at rest, after the worst of
the frosts are over, the end of February being usually suitable;
but the former period is generally acknowledged to be the better,
especially for fruit-trees. The cuts should be clean and level, and
when a saw is used should be made smooth with a chisel and covered
with grafting wax. In all cases as little wound as possible should
be presented. Root-pruning has for its object the suppression of
over-vigorous growth and the restoration of old trees to a bearing
condition. It consists in taking off all the small fibres, shortening
the long roots to within 6 or 8 in. of the stem, and cutting away any
bruised or injured roots before the trees are first planted out. The
mode of procedure in the case of old or unproductive trees is to
open the earth in autumn 3 ft. from the stem of the tree, and to saw
through two-thirds of the strongest roots. The opening is then filled
in with fresh mould. Should the growth still be too vigorous, the soil
must be opened again the following season and the remaining roots cut
through, care being taken not to injure the young fibrous roots.
Prunus.--Beautiful early-flowering trees, which will grow in any soil,
and can be increased by seeds or suckers.
Ptelia Trifoliata (_Hop Tree_).--This is very suitable for planting on
the borders of still waters, where its long frond-like leaves, which
turn to a golden yellow in autumn, produce a fine effect. It blooms in
June, and is propagated by layers. Height, 10 ft.
Pulmonarias (_Lungworts_).--Hardy perennials that require but little
attention; may be grown in any common soil, and propagated by division
at any time. They flower in April and May. Height, 1 ft.