164 ROCK GARDENING FOR AMATEURS 



to flower, coining into bloom in late summer and autumn. 

 P. capitata is a biennial, and must be raised annually 

 from seeds, which should be sown in the autumn. To 

 grow it successfully, a cool, shady place must be selected 

 where it can get plenty of moisture. 



P. denticulata, from the Himalayas, is a handsome 

 plant that is well known and much appreciated in gardens. 

 It is valuable for naturalising in moist, shady places, 

 like fern borders, where it will establish itself from self- 

 sown seedlings. In rich soil it is very robust, with large 

 leaves and stout stems twelve inches high, bearing 

 globular heads of deep lilac flowers in early spring. 

 There is also a pure white variety. P. cashmiriana 

 is a form of this with more densely packed heads of 

 flowers, usually paler in colour, while the lower surface 

 of the leaves is covered with yellow powder. 



P. Forrestii. A recent introduction from Western 

 China, with large leaves and golden yellow flowers, 

 closely resembling, but larger than, the Common Cow- 

 slip. So far it has only proved hardy in the warmer 

 parts of the country. It is a long-lived plant in its home, 

 forming long woody stems which hang down the faces 

 of the cliffs, bearing rosettes of leaves at the end. The 

 flowers are fragrant. In a cold frame it may be kept 

 over the winter if it is not allowed to get frozen. 



P. frondosa. A large and beautiful form of P. far- 

 inosa from the Balkans. It is a good perennial, and 

 will stand our winters in a sheltered corner of the rock 

 garden. After flowering the plants may be divided, 



