2i8 ROCK GARDENS 



Deep, well-drained soil, composed of sandy loam, leaf-mould, and 

 brick rubbish. Dark green spiny leaves with an overlying slightly 

 grey or glaucous shade. Forms close tufts 6 to 8 inches high. 

 It is a slow-growing plant, freely producing bright rose-coloured 

 flowers on arching, one-sided spikes during July. The flowers 

 are rather longer than those of A. gluinaceum. Propagation by 

 layers and cuttings. This is one of the most attractive and choicest 

 of rock plants. It requires firm planting. 



Acanthus (Acanthaceae) 



There is only one variety of this genus suitable for the rock 

 garden, namely, A. P erringi {syn. Roseus Caroli and Alexandri). 

 Ordinary soil in a sheltered position. Leaves long and lanceolate, 

 low-growing habit. Flower-spikes about I2 to i8 inches high, each 

 producing twenty-four to thirty blooms of deep pink flowers. Quite 

 hardy and vigorous. A useful and attractive new introduction, 

 though it has not the brilliancy of some alpines. 



AcHiLLAE (Compositae), Yarrow 



A numerous, though not particularly interesting family of 

 Compositae, some of which, owing to their rampant growth, are 

 suitable only for the herbaceous border ; but the dwarfer-growing 

 kinds come in useful for grouping in the rock garden, and are 

 easily grown and increased. Some of the higher alpine kinds are 

 liable to become " leggy " in our open winters and will occasionally 

 require division and replanting. Most of the Achilleas are good 

 subjects for the wall garden. All like a hot, dry position. 



A. ageratifolia {syn. Anthemis Ai'zoon).— Sunny aspect. Light 

 sandy soil. A neat and spreading plant about 5 inches high, of 

 moderately rapid growth. The crinkled leaves, which are narrow 

 and tongue-shaped, are covered with a white down. White, daisy- 

 like flowers are freely produced in June. It is easily cultivated 

 and readily increased by division or cuttings, and quite hardy. A 

 useful plant on account of its silvery foliage. 



A. aegyptiaca (syn. taygetea). — Requires a well-drained, sunny 

 position. Rather a tall-growing, shrubby plant of 12 to 18 inches 

 high. Not a very rapid grower. Stems and finely cut fern-like 

 leaves of a silvery colour. Handsome heads of pale yellow flowers 

 during August. Easily increased by cuttings. This Achillea is 

 not very hardy, except in well-drained, sunny, and sheltered spots. 

 A useful and attractive, half-shrubby plant for the higher parts of 

 the rock garden. 



A. alpina. — Indifferent to either soil or position. Grows 6 to 



