CHAP. VII.] 
ESPALIERS. 
215 
extend under the gravel walks, which are 
purposely left hollow; but this defeats the 
purpose for which they are to be attracted to 
the surface, for the spongioles will be as 
effectually excluded from the air under a 
compact coating of gravel, as if they were 
buried many feet deep in the soil. If an un¬ 
derground wall is built along the inner side of 
the espalier border to confine the roots of the 
trees, stones should be fixed in it at intervals, 
with holes made in them for the reception of 
the espalier rails, which should be run in 
with pitch. These rails should be about 
nine inches asunder, and they may be kept 
together at the top with a transverse rail, to 
which they should be nailed. The inconve¬ 
niences of espaliers are the very great trouble 
of training them and keeping them within 
bounds; the rough and untidy appearance 
which their spurs assume when the trees 
begin to get old; and the numerous diseases 
to which the trees are liable, from their un¬ 
natural position and constant cutting in, 
and which always render espalier trees short¬ 
lived. 
Standard fruit-trees. —Tall standard 
