HARDY PERENNIALS 
Fig. 124. Day Lity — Hosta caerulea 
This principle of limiting one’s self to a comparatively small 
list of the oldest and commonest plants has to be adopted by the 
professional landscape gardener, in fact, as well as by the layman. 
It is merely a question of drawing a line. The landscape gardener 
should know a considerably longer list of plants than the grocery- 
man or the banker; the professional plantsman will know a great 
many more than the landscape gardener; but even the nuttiest 
plantsman must stop somewhere. No living man, sane or crazy, 
can know all the good plants in the world. 
The first duty of the student, therefore, is to ascertain what 
are the leading genera of old-fashioned plants, next to learn what 
are the best species or varieties in each group. This can be done 
only amongst the plants themselves, whether they are growing in 
gardens, nurseries or in the wild. All these separate sources should 
be utilized. The plants should be studied everywhere. 
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