Royal Horticultural Society <br/><br/>
Plant guides pernnials 
The Royal Horticultural Society. 
 - 6th ed. 
 - London  Dorling Kindersley  1996 
 - 352p., col. illus.; 21cm. 
<br/><br/><label>Dewey Class. No.: </label>635.932  / R95P