274 FLORA HTSTORICA. 



every second or third year, as it weakens the plant, 

 and prevents its producing fine blossoms. 



All these plants thrive best in a rich and moist 

 loamy soil ; for, when planted in a poor dry soil, 

 their flowers are never large, and the plants fre- 

 quently perish in the summer for want of moisture. 



