its leaves, and thus allow the grass time to complete its 
growth in the fall sun before winter sets in. Walnuts, 
of course, require a good deal of room, but careful prun- 
ing will develop a proper shape for any situation. There 
are certain disadvantages — the tree has a number of in- 
sect pests. The most important is the Walnut Datana, 
whose larva spin a web, housing several hundred caterpil- 
lars, destroying the foliage while safety inclosed in 
their tent. Arsenate of Lead is a certain control. Some 
objection might be raised to the fruit falling on pedes- 
trians and automobiles, but ordinarily, the squirrel pop- 
ulation of a town or city will be equal to the task of 
harvesting the fruit before it reaches a dangerous size. 
For lawn trees, one might use the named varieties, since 
they produce superior nuts, but for street use, just any 
American Walnut will be satisfactory. While the tree is 
not exacting in its soil requirements, we cannot expect 
good growth when it is planted on a degraded site. 
WILLOW 
The MillovisiSalix) are all trees requiring more 
than the usual amount of water. They grow extremely fast 
and their life span is usually short. They have a defin- 
ite place in landscape architecture since no other tree 
has quite the characteristics and habit of the Willow. 
They are the first to unfold leaves in Spring and the 
last to shed them in Fall. Almost innumerable varieties 
occur, but only a few are found in nursery catalogues. 
The weeping kinds, with long pendant branches are unique 
and have no rivals. Some Willows grow into forest trees, 
others never grow very large and some are shrubby. There 
is much variation in foliage, in both size and color. 
Willows would not be satisfactory as street trees— they 
are altogether lacking in strength and are too easily 
damaged by storms. Willows have some insect pests, but 
these are no more difficult to control than those on 
other trees. 
YELLOW 
Here is k poorly known tree having some outstanding 
characteristics. The Yellow Wood (Cladrastis lutea) is 
hardy in the St. Louis region and would develop into a 
lawn tree of great size and beauty. The bark is steel- 
gray, smooth, and quite distinct. The flowers are 
26 
