SHRUBS ARB TREES. 
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feet high, cutting their leaders out so as to leave a tier of branches 
as nearly as possible at the same height on the four trees. The 
following year see to it that none of these upper branches turn up 
to make leaders, and if necessary tie them down to a horizontal 
direction. By attending to this for two years the top tier of 
shoots will make a horizontal growth, which will meet in a few 
years over head, and form a table-like top of foliage. But to 
insure this effect, the tree must be watched for some years to 
prevent any strong shoots from taking an upward lead, and 
thus draw the sap away from the horizontal branches. After 
these have met over head, and form a sufficient shade, the part 
above may be allowed to grow as it will. The check and 
change in the growth of the trees by such manipulation, carried 
on for several years, insures a novel and picturesque form for 
the group that will be permanent. As the white pine attains great 
size at maturity, it is not well to attempt such an arbor on quite 
small grounds. 
Deciduous trees being more subject to insects on their foliage, 
are less desirable than evergreens for these uses, but they spread 
at the top more rapidly, can be more quickly grown to the re- 
quired forms, and are covered at certain seasons with beautiful 
and fragrant blossoms ; so that in variety of attractions some of 
them are unequalled by any evergreens. The latter wear through- 
out the year the beauty of constant cheerfulness, while the former, 
with the changing seasons, are alternately barren of graces, or 
bending with foliage and glowing with blossoms. 
For archways there are no finer deciduous trees than the 
English hawthorns, and the double flowering scarlet thorn, Crcete- 
gus coccinnea flore plena. They can be planted at the sides of foot- 
path gates, in the same manner as recommended for the hemlock, 
and it will only be necessary to trim them on the inside, so as to 
keep the opening unincumbered ; as the hawthorns bloom best on 
their extended garland-like branches. But they should be trimmed 
enough to prevent any decidedly straggling outline, to show that 
they are intended as artificial adaptations for a purpose. Fig. 37 
shows a suitable form for a hawthorn arch. 
For bowers, or umbrageous groups surrounded by open sunny 
