146 TREES AND SHRUBS 



class are well worth study by those whose locality 

 admits of their cultivation. 



For dry, sunny, and stony banks Rock Roses may 

 be chosen, but the position must be wind-screened, 

 a more important factor in the question of their 

 hardiness than cold. The large-growing Gum Cistus 

 is well known and tolerably hardy everywhere, and 

 so also is C. laurifolius, but there are several most 

 desirable species of dwarfer growth, such as the 

 white, crimson-spotted C. lusitanicus, the pink-flowered 

 C. villosus, the bright-red C. crispus, and the pure 

 white C. florentinus, which are quite happy in sheltered 

 rock walks especially by the sea ; they have been 

 also grown with success in many colder situations 

 inland. The Cistineae, at best, are somewhat short- 

 lived, and lose vigour and power of resistance as 

 they grow older. Keep up, therefore, young, thrifty 

 stock by yearly cuttings to fill up inevitable gaps, 

 which is a matter of no cultural difficulty. Where 

 Rock Roses are out of the question, their place may 

 worthily be filled by the hardier shrubby Helian- 

 themums, though they differ greatly from Cistineae 

 in their trailing habit and smaller flowers. The 

 breadths of brilliant colour given by these Sun Roses 

 while in bloom are invaluable, and may be en- 

 joyed to the full in almost any locality, while the 

 many variations of tint, from deep green to ashen 

 grey, in their leafage should also be taken into con- 

 sideration, as it increases their usefulness when out 

 of flower. 



No list of good shrubs for the Rock Garden would 



