THE GROWING OF THE ORNAMENTAL PLANTS 231 
necessary to give the tank some kind of lining. Clay is often 
used. The bottom and sides of the tank are pounded firm, 
and then covered with 3 to 6 in. of clay, which has been 
kneaded in the hands, or pounded and worked in a box. 
Handfuls or shovelfuls of the material are thrown forcibly upon 
the earth, the operator being careful not to walk upon the work. 
The clay is smoothed by means of a spade or maul, and it is then 
sanded. 
The water for the lily pond may be derived from a brook, 
spring, well, or a city water supply. The plants will thrive in 
any water that is used for domestic purposes. It is important 
that the water does not become stagnant and a breeding place 
for mosquitoes. There should be an outlet in the nature of a 
stand-pipe, that will control the depth of water. It is not neces- 
sary that the water run through the pond or tank rapidly, but 
only that a slow change take place. Sometimes the water is 
allowed to enter through a fountain-vase, in which water plants 
(such as parrot’s feather) may be grown (Plate X). 
In all ponds, a foot or 15 in. is sufficient depth of water 
to stand above the crowns of the plants; and the greatest depth 
of water should not be more than 3 ft. for all kinds of water- 
lilies. Half this depth is often sufficient. The soil should be 
1 to 2 ft. deep, and very rich. Old cow manure may be mixed 
with rich loam. For the nympheas or water-lilies, 9 to 12 in. 
of soil is sufficient. Most of the foreign water-lilies are not 
hardy, but some of them may be grown with ease if the pond is 
covered in winter. 
Roots of hardy water-lilies may be planted as soon as the 
pond is clear cf frost, but the tender kinds (which are also to 
be taken up in the fall) should not be planted till it is time to 
plant out geraniums. Sink the roots into the mud so that they 
are just buried, and weight them down with a stone or clod. 
The nelumbium, or so-called Egyptian lotus, should not be 
transplanted till growth begins to show in the roots in the 
