MONTHLY CALENDAR. 



219 



verting it. This process buries the leaves and rubbish, without injuring the 

 roots. The growth of shrubs should also be regulated by pruning and training, 

 as the cleaning proceeds. Common laurels and lilacs will often be found over- 

 riding rhododendrons, or other shrubs : the most worthless should alwa3's be 

 removed, or boldly cut in. Rhododendrons are often very effective as margins 

 to masses of other shrubs, and they are invaluable in groups bj' themselves. 

 No collection of shrubs, and no garden, should be considered complete 

 without an assemblage of hardy heaths. They flower chiefly at the end of 

 summer and during the autumn, and the species of Carnea blooms early in the 

 spring. For beauty of habit, delicacy of tint, sweetness of perfume, usefulness 

 and durabihty of bloom, they have few rivals. They are also cheap. Good 

 strong bushy plants, of many varieties, can be supplied by most of our leading 

 American nurserymen at less than a shilling apiece in hundreds. In man}'- 

 parts of the country they can be collected from the hills for nothing. They 

 can also be increased by cuttings, layers, and seed. The one great drawback 

 to their culture is, that generally they must have peat-earth to bring them to 

 perfection or maintain them in health. I have had carnea, and several other 

 varieties, do very well in a mixture of loam and leaf-mould. As a rule, how- 

 ever, they all thrive best in a hard, sandy, gritty peat. Bog-peat is hardly fit 

 for their growth, unless it is liberally mixed with sharp sand and the debris of 

 freestone rocks. Drjiiess and hardness of soil seem to be essential to their 

 maintenance in health. No one can have traversed heath- clad mountains 

 without being convinced of this. From six inches to a foot of soil is more than 

 most of them find in their natural habitats. It must be borne in mind, how- 

 ever, that in such situations the whole surface is covered with plants ; conse- 

 quently the evaporation of moisture from the soil is checked by the leaves and 

 branches. For their culture in the garden, from 18 inches to 2 feet of such 

 soil, resting on a dry bottom, would be desirable. Beds or groups of hardy 

 heaths would make a charming display. Such groups would harmonize well 

 "with the different fir-trees in or near to the Pinetum. Nothing could exceed 

 their beauty, congruity, and adaptabilty, as furnishings for rock-work. Peat- 

 earth could easily be introduced among the crevices, between stones, &c., and 

 the heaths introduced there. They would thrive admirably in such situations, 

 and contrast well with the ferns and other plants that find a congenial home in 

 such localities. 



572. The following are the varieties most generally cultivated for sale : — 



Erica australis. 



„ herbacea. 

 ,, ,, carnea. 



„ cinerea alba. 

 ,, ,, rosea. 



„ „ rubra. 



„ lanceolata. 



,, mediterranea. 



Mackaiana. 

 striata. 

 Tetralix rubra. 



hibernica. 



Erica Tetralix alba. 

 „ vagrans carnea, 

 „ vulgaris alba. 

 „ „ „ minor. 



„ „ coccinea. 



„ ,, decumbens. 



„ „ Hammondii. 



„ „ pumila. 



» „ pygmsea. 



„ „ vanegata. 



rigida. 

 „ variabilis. 



