220 HARDY PERENNIAL PLANTS. 



feet. S. Sieboldii is quite hardy in this locality ; it makes a fine plant 

 for pots or baskets, but it does not associate well with other plants in 

 the same receptacle. S. acre, S. a. aureum and S. sexangulare form dense 

 growths from 2 to 3 inches in height. The yellow flowers are produced 

 in great abundance about the beginning of June ; their mossy-like growths 

 are attractive all the year round. S. spurium (S. stoloniferum ) has very 

 handsome pink flowers, produced sparingly from midsummer till late in 

 Fall. All of the species named are increased by division. 



SEMPERVIVUM (Houseleek) Dwarf succulent plants, well suited for 

 dry, exposed positions in the rockery. The hardy species are easily in- 

 creased by division. S. tectorum is the species commonly grown. S. 

 arachnoideum has small rosettes of leaves connected at the tips by a 

 cobweb-like formation. Other well known species are S. californicum, 

 S. Funckii, S. hirtum and S. soboliferum. They will thrive in almost 

 any kind of soil. 



SILENE (Catchfly) Among this very large genus there are three per- 

 ennial species, each one growing only a few inches tall, which are among 

 our finest rockwork plants. S. Schafta has bright purple flowers; it is 

 a very deep rooting species, and stands dry weather well, keeping in 

 bloom for several months. It can be raised from seed; or old plants 

 divide well in October. Dig up the plant carefully, saving all of the 

 roots, and in dividing give each piece as much root as possible; put in 

 pots and keep in a cold frame for the Winter. S. alpestris is a neat 

 growing little plant with white flowers; easily raised from seeds. S. 

 maritima forms a dense carpet of growth, the branches from a single 

 plant covering a large surface. The flowers are white and are rather 

 showy; they last only a short time, however. The foliage is handsome 

 for the greater part of the year, being very neat and of a whitish cast. 

 Seeds ripen in abundance; they should be sown early in September. 



SPIRAEA (Headow Sweet, Goat's Beard) There are several very 

 handsome herbaceous plants in this genus; all of them are of easy culti- 

 vation. They are best increased by division either in Fall or early in 

 Spring. S. aruncus is a variable species; the plant found in the Eastern 

 States seems much more dwarf than the one commonly cultivated in 

 European gardens. To grow this plant to best advantage it should be 

 given an isolated position. It usually attains a height of from 3 to 6 

 feet, according to variety. S. astilboides is dwarfer than the above 

 named; flowers white, borne in dense panicles. S. filipendula is a valu- 

 able rockwork plant, the finely cut leaves remaining green all the year 

 round. The flowers, especially those of the double variety, are showy. 

 S. palmata is without question one of the handsomest flowered herba- 

 ceous plants in cultivation, but unfortunately other worthless kinds are 

 often sold for it. The flowers are bright crimson, in large panicles; the 

 leaves are palmately five to seven-lobed. S. ulmaria (Queen of the 

 Meadow) has creamy white, very fragrant flowers. The plant grows 

 from 2 to 4 feet high, and, like all of the others, it delights in damp soil, 

 with partial shade during midday. They are all best increased by 

 division. 



