The Heath Tribe. 583 



such as are suitable for the situation where it is wished to 

 grow them. But temperature is not the only element of a 

 climate. Humidity of the atmosphere and light are other 

 elements which must be taken into account. Broadly speaking, 

 we may say that all the Ericaceae demand a certain amount of 

 moisture in the air surrounding them. This moisture may 

 have its source in the mists which frequently envelop the 

 mountains where they grow ; or it may be due to the vicinity of 

 the sea, lakes, marshes, or water-courses. The site and aspect 

 for these plants are also of great importance. For those species 

 loving a marshy habitat, a low, flat, spongy soil is naturally 

 the best ; but these species are few in number and less generally 

 cultivated than the others. All the other species prefer a 

 sloping bank of eastern or northern aspect, but it should be 

 sheltered from the winds. If, therefore, there are natural or 

 artificial mounds in a, garden, the shady side of these should be 

 selected for planting clumps of Rhododendrons, etc. In the 

 absence of small hills, raised beds can be substituted ; but if 

 the natural drainage be insufficient, a layer from six to nine 

 inches thick of coarse gravel or some other open material will 

 be necessary in a low situation. 



The site having been selected, and the form of the planta- 

 tions decided upon, the natural soil should be taken out to a 

 depth of eighteen inches or two feet; and if the subsoil is of 

 a heavy impervious nature, a layer of draining materials from 

 six to nine inches thick put in at the bottom and filled up 

 with peat, roughly broken but not sifted. This earth is thrown 

 up into a mound high enough that after sinking it will still be 

 a little above the general surface of the ground. The thick- 

 ness of this bed will vary according to the size of the species 

 it is intended to plant. It will readily be un4ersood that a 

 greater depth of soil will be necessary for the large-growing 

 Rhododendrons than for those of smaller growth, and such 

 as Heaths and Vacciniums. 



In some parts of the country there is a difficulty in pro- 

 curing peat, and, besides, a great deal of it is too poor to use 

 alone with advantage. It may be enriched by the addition of 

 thoroughly rotten leaf-mould with a little sharp sand, or a corn- 

 post may be substituted for it consisting of equal parts of sand 

 and vegetable mould. But the fibre of the peat being one of 

 its important elements, no substitute can equal it. The top- 

 spit of earth in an old wood is usually rich in humus and very 



