424 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



C. collina is a pretty, neat-growing plant, bearing flowers of deep blue ; 

 it should be grown in well-drained compost of brick rubble in a sunny 

 position. C. excisa, C. cenisia, C. Waldsteiniana, C. acutangula, and 



C. Zoysii are all rare and beautiful species, and not much seen in the 

 rock garden. They are more difhcult to grow than the others 

 mentioned, and require a well-drained, sunny position, in a good gritty 

 compost, and should be top-dressed twice a year. They are quite 

 at home in the moraine. 



Sedum (Stonecrop). — Although many in this extensive genus are 

 weedy and worthless plants, a great number are exceedingly attractive 

 and indispensable for the rock garden. Nearly all Sedums prefer poor, 

 gritty soil, in full sunshine. S. oreganum (= obtusatum of gardens) is a 

 Californian plant with bright emerald-green leaves, which take a 

 crimson tint in autumn and winter. The crimson stems bear yellow 

 flowers ; it should be planted in full sun. 5. pulchellum, an 

 American Stonecrop, is a pretty species with rosy-pink flowers arranged 

 in several spreading and recurved branchlets, bird's-foot fashion, 

 with numerous spreading stems. It requires a shady and rather 

 damp position on the flat. S. k amis chat i cum and S. k. variegatum 

 are two good plants, and should find a home on every rock garden. 

 S. spathulifolium, a North American species and one of the best, has 

 dense rosettes of fleshy glaucous leaves and pink stems bearing 

 yellow flowers. S. Sicboldii is a Japanese species with semi-erect 

 stems clothed with round leaves borne in threes, and with terminal 

 heads of pink flowers. It is best planted behind a stone where it can 

 hang over, in a sunny sheltered position ; in the autumn the glaucous 

 foliage will change to a rosy-coral hue. 



Dianthus. — The ' Pinks ' are almost all easy to grow. They prefer 

 gritty limestone soil, and chinks between stones or well-drained ledges. 

 The tufty species should be packed between sloping stones or in upright 

 or horizontal strata. D. alpinus and D. cal-alpinus are lovely alpine 

 plants with very large flowers. They require a south aspect, sheltered 

 from midday sun, in good deep fibrous loam, grit, and leaf-mould (not 

 too dry) ; top-dress every autumn in a similar compost, and increase by 

 cuttings and seeds. Wire-worms and slugs are very troublesome to 

 these two plants. D. glacialis is a miniature species from the Alps, 

 and D. neglectus is a dwarf tufty species with large clear pink flowers. 

 The true form has the underside of the petals a soft buff colour. 

 These two are the prettiest of all the Dianthus. They should be given 

 a south-west aspect in crevices low down, so that the roots get plenty of 

 moisture, in a compost of gritty loam ; increase by cuttings, division, 

 and seed. D. Freynii, from Hungary, is probably the smallest Dianthus 

 we have, but a very interesting one on account of its small, bright 

 flowers, and neat, compact habit. It thrives best on a sunny bank, 

 and, like all the Pinks, needs top-dressing once or twice a year. 

 Dianthus is a large and varied genus, and there are many other species 

 which should find a home in the rock garden, such as D. caesius, 



D. dcltoidcs, D. arcnarius, D. dependcns, and D. graniticus. 



