BROOKLYN BOTANIC GARDEN 
LEAFLETS 
THE BROOKLYN INSTITUTE OF ARTS AND SCIENCES 
Series VII Brooklyn, N. Y., April 30, 1919 
No. 3 
THE ROCK GARDEN 
The Rock Garden of the Brooklyn Botanic Garden was con- 
st! ucted in the spring of 1916. The rocks are, for the most part, 
glacial boulders which were uncovered in the course of grading 
operations on other parts of the grounds. These boulders were 
very unprepossessing material for the construction of a rock 
garden, their rounded contours almost prohibiting any natural 
and artistic effects from being obtained. Their hard, impervious 
surfaces are far from ideal from the standpoint of the cultural 
requirement of the alpine plants, which revel in rocks of a loose, 
porous nature to which their roots may cling. In spite of these 
disadvantages, one is cheered by overhearing visitors comment- 
ing on the “wildness” and natural appearance of the garden. The 
fact that over six hundred species and varieties are now growing 
in the garden, many of them alpines considered very intractable 
in this part of the country, is testimony that the difficulties of 
cultivation have, in part, been overcome. In order to provide 
quarters for plants that delight in rock crevices, a number of the 
larger boulders were split and the fissures filled with suitable 
soil. That all of these crevices are not occupied with happily 
thriving plants is partly due to the taking propensities of some 
of our visitors, who remove the plants almost as fast as they 
are set out. 
What is known in garden parlance as a “moraine garden” 
was constructed in 1917 to care for some of the more capricious 
alpines. It was made by excavating the soil over a small area of 
the rock garden to a depth of eighteen inches or two feet, and 
replacing it with a mixture of three-quarter inch crushed stone, 
five parts; sand, one part; and leaf mould, one part. This pro- 
vides perfect drainage, and encourages the roots to penetrate 
deeply where it is cool and moist, a most important point in the 
cultivation of alpines. It also ensures perfect ripening of the top 
