THE HORTICULTURAL SOCIETY OF NEW YORK 



ROCK GARDENS 



By Montague Free, Horticulturist, Brooklyn Botanic Garden. 



Lecture delivered December 13, 1923, American Museum of Natural History. 



(Mr. Leonard Barron, presiding) 



DURING a recent trip to England for the purpose of study- 

 ing garden conditions, the fact was noted that in every garden 

 visited alpine and rock plants were exhibited in some form or an- 

 other. The popularity of alpine and rock gardening in England 

 is not a passing fad as is proved by the fact that, as long as 10 or 

 15 years ago, rock gardening seemed to be at its zenith, and yet, 

 since that time, there have been great advances especially along the 

 lines of artistic construction and the introduction of new plants. 

 Today rock gardening is more popular than it has ever been in the 

 past. The beautiful results that can be obtained with an artistically 

 planned rock garden and the fascinating interest of the alpine and 

 rock plants that are used to embellish it, account for the popularity 

 of this class of gardening in England, and the rapid strides that it 

 is making in this country. 



Rock gardens as we know them undoubtedly originated in order 

 to provide proper cultural conditions and suitable settings for the 

 plants of the high mountains. These aristocrats of the mountain 

 tops need special treatment in order to enable them to thrive under 

 cultivation in lowland regions of the temperate zone and this can 

 best be provided in a rock garden. The thing to remember in the 

 construction of an alpine and rock garden is that the majority of 

 these plants require a soil that is gritty and well drained, for most 

 of them resent stagnant water at the roots. In making a rock 

 garden, therefore, one should provide perfect drainage and a 

 sandy, porous soil to be used in filling in the spaces between the 

 rocks. When a soil of this kind is used, it is easy, by the addition 

 of crushed limestone, bluestone screenings, peat, or humus, as the 

 case may be, to modify the soil in such a way as to make it suitable 

 for the more pernickety plants. The purpose that the rocks serve 

 in a rock garden is that of giving shelter, conserving moisture by 

 preventing evaporation from the surface, and helping to keep the 

 ground cool. 



