DESCRIPTIVE AND SELECTIVE. 235 



growing, if only to form a groundwork for bulbs. It 

 is evergreen and is bright both in Summer and V^inter. 

 There is a yellow-leaved variety called aurea. The 

 Herniarias thrive in almost any firm soil, and may be 

 propagated by division in Autumn. 



HIERACIUM.—Oi the Hawkweeds one of the best 

 is gymnocephalum, which has downy leaves and bears 

 loose spikes of yellow flowers in July. The Hawkweeds 

 thrive in almost any soil, and may be increased by 

 division. 



HOUSTONIA CMRULEA (Bluets).— A dainty 

 little American Alpine forming a close carpet of verdure, 

 studded with Httle bluish flowers only an inch or two 

 above the soil in Summer. It is suited by a loamy or 

 peaty soil, and may be propagated by division between 

 Autumn and Spring. It is apt to suffer if grown near 

 luxuriant things hke the Rock Cresses, and should be 

 protected from their encroachments. 



HUTCHINSIA ALPINA,—A pretty Alpine of low 

 growth, which produces a sheet of snowy blossom in 

 Spring only a few inches above the ground. It will 

 thrive in ordinary soil if not smothered by coarse 

 plants. It may be raised from seed in a frame in 

 Spring, or by division between Autumn and Spring. 



HYPERICUM (St. John's Wort).— Most of the 

 Hypericums are too large for small rock gardens, 

 although most useful for planting in dry hot borders. 

 A few are suitable, however, and among them may be 

 named reptans, a Himalayan species, which bears 

 prostrate masses of yellow flowers in June. NummU" 

 larium is also a trailer, and Olympicum, which is of 



