THE USE OF ORNAMENTAL PLANTS 307 



forming a dense mat on the ground and is characterized by 

 gray-green leaves and small purplish- white flowers. It does 

 not require mowing unless it is desired to keep the flowers 

 removed. A lawn of this material never has the beautiful 

 appearance of well kept Kentucky blue-grass. 



One interesting point regarding Lippia canescens is that 

 it is established in the first place from cuttings, as very few 

 seeds are produced. These cuttings are put in the ground a 

 few inches or even a foot apart, and spread quickly until they 

 form a carpet. 



432. Ground cover. Frequently it is desired to have the 

 space under trees and shrubbery covered with a solid mass of 

 green material. A number of plants can be used for this 

 purpose ; the requirements are that they grow fairly rapidly 

 in the shade and form a mat of foliage. The two most com- 

 monly used for this purpose are English ivy and Vinca minor 

 or periwinkle. Both of these are evergreens which thrive in 

 moist shady situations. 



THE LANDSCAPE PLAN 



With the material the landscape-gardener has at his dis- 

 posal, he can produce widely varying effects. The type of 

 plants which he uses and the way he groups them gives to 

 the landscape that particular quality which is known as 

 "style." 



433. Formal style. There has always been a tendency, 

 happily much more common formerly than now, to arrange 

 grounds after the manner of definite geometrical designs, as 

 though a garden were an illustration of a Euclidian proposi- 

 tion. In this style of landscape-gardening, all lines are 

 perfectly straight, or assume the forms of circles, five-pointed 

 stars or triangles, or other regular figures. The hedges are 

 kept closely clipped, the shrubs are trimmed into odd and 

 sometimes grotesque shapes. Flowers and other ornamental 

 plants may be used, but the vegetation is invariably sub- 



