REPORT OF THE SUPERINTENDENT OF GARDENS. 63 



On this the soil is raised 18 inches above the level of the water, sup- 

 ported at the sloping sides by a rustic wall of small stones. Plants of 

 the Japnn bamboo-cane have been thickly set on the margin, and more 

 spariugly dotted over the smface of the bed, for the parjiose of affording 

 a slight shelter and shade to the rhododendrons. These brilliant flow- 

 ering plants have been found to grow and thrive to perfection in such 

 positions. They are provided with fine hair-like roots that ramify near 

 the surface, and are easily destroyed if the soil becomes dry ; hence a 

 soil that is kept equally moist without reaching saturation is favorable to 

 their extension and preservation ; the whole secret of rhododendron 

 culture depends upon this condition of the soil; for, although they are 

 natural to shady forests, they become habituated to sunshine and retain 

 their verdure in open sites, provided the roots are constantly supplied 

 with moisture. Surface-evaporation can be retarded by mulching the 

 roots with decaying leaves, grass-cuttings from the lawn, or strawy 

 manure from the barn-yard. The magnificent display of rhododendrons 

 in flower at the International Exposition has created a widespread 

 interest in their culture ; from comparative obscurity they have suddenly 

 been raised to a popularity which they deservedly merit as regards orna- 

 mental effect in pleasure grounds and public parks. 



The native azalea is a close family relation of, and associates well 

 with, the rhododendron, requiring similar conditions of soil and position. 

 A portion of the bed is reserved for plants of Kcdmia latifolia, An- 

 dromeda floribunda, Ilex {Prinos) verticellata, Itea virginica, and Clethra 

 alnifolia ; the trailing arbutus, the partridge-berry, and others of 

 similar habit are planted as undergrowths. 



The interest felt in the introduction of new economic plants for exper- 

 imental trial leads to constant demands upon the Department for seeds 

 and plants of species not adapted to the climate or locality in which 

 these experiments are proposed to be made. Among those in frequent 

 demand the following are noted, with remarks on their adaptability or 

 fitness for cultivation in this country : 



COFFEE. 



The successful culture of the coffee-plant, Coffea arahica, in auy por- 

 tion of the United States is exceedingly problematical. There is a con- 

 stant demand for plants for experimental purposes, which the Depart- 

 XDartment is unable to supply, owing to the difl&culty of procuring fresh 

 seed. It is barely possible that in Southern California, or in Southern 

 Florida, localities may be found where it may succeed; but these are the 

 only regions where further experiments in coffee-culture need be made. 

 Authorities on coffee-production very generally coincide in the opinion 

 that it cannot be profitably grown in any climate where the temperature 

 falls as low as 50° F. at any period of the year. It may be presumed, 

 however, that the amount of summer-heat required to mature the berry 

 is a more potent factor in the elements favoring success than is the mere 

 ability of the plant to endure for a brief time a certain degree of cold; 

 for it is well known that culture can extend a controlling influence so 

 far as to render plants better fitted to endure a temporary low temper- 

 ature without inducing any perceptible injury to their vital forces ; but 

 no modification of ordinary cultural appliances can increase the supply 

 of atmospheric heat in a climate so as to exert any favorable influence 

 on its vegetation. Since the introduction of coffee-culture in Liberia, 

 attention has been directed to the superior size of the berry produced in 

 that country. For a time it was supposed to be one of the varieties of 



