122 GARDENS OF ENGLAND 



constantly increase in strength, but do not spread 

 about, whilst others are of a roaming nature, their 

 stolons and rhizomes wandering over a large space, 

 and quickly spreading across the roots of other 

 varieties. In natural lakes or ponds it is impossible 

 to prevent this confusion ; but this irregular growth 

 should not be permitted in artificial basins and 

 aquaria, where each plant in the collection should 

 remain distinct and thrive independently ; besides, 

 it would not only produce inextricable confusion 

 amongst the plants, but the weaker would be 

 smothered by the stronger. In order to obviate 

 this difficulty it is indispensable that the basins 

 should be divided into several compartments by 

 partitions which should not be higher than three- 

 fourths the depth of the water in such a way that 

 they only prevent the roots and rhizomes from 

 meeting, without preventing the leaves from inter- 

 mingling on the surface. 



A depth of two feet is sufficient for the tanks. 

 A bed of earth six inches deep on the bottom 

 of the basins will suffice for the culture of water- 

 lilies ; it ought to be as free as possible from gravel 

 and stones. The best soil is somewhat heavy 

 loam from the garden or meadow, but that 

 composed of leaf-mould and alluvial matter is 



