POTTED FLOWERING PLANTS ' 347 



perature should be kept no higher than 60. The heaths 

 are particular in regard to soil moisture ; too much or too 

 little water is injurious to them. The pots need to be gone 

 over carefully each day and kept at just the right degree 

 of moisture. They should never be allowed to wilt, but 

 during the winter months, they require less w r ater than 

 when growing rapidly. After flowering, they should be 

 trimmed into symmetrical forms. Summer pinching is 

 also often necessary to accomplish this. The foliage 

 should riot be allowed to drop from the lower part of the 

 stem. Heading them back has a tendency to prevent this. 

 The plants may be carried through several years, pro- 

 vided care is taken in the summer treatment. They 

 should be re-potted in June each year, and great care 

 taken to keep the root system active. Ericas require 

 abundant ventilation at all times. They are susceptible 

 to attacks of mildew, and if this appears, they should be 

 sprinkled with sulfur. During the summer, great care 

 should be taken that the plants do not dry out. 



AZALEAS 



534. Botanical classification. Order, Ericaceae ; genus, 

 Azalea (from Greek azaleos, dry. Linnaeus believed them 

 to grow in dry localities) ; species : sinensis, gandavensis, 

 calendulacea , Vaseyi, indica. The first four species are 

 hardy. In most of them, the flower-cluster precedes or 

 accompanies leaf development. Azalea indica is an 

 evergreen shrub which requires greenhouse cultivation 

 (Fig. 40). Genus often included in Rhododendron. 



535. Botanical characters. Azaleas are shrubs with 

 persistent or deciduous foliage. The flowers are produced 

 in showy, terminal clusters. The corolla is five-lobed, 



