8 NATURE STUDY AND AGRICULTURE 
All herbaceous perennials die down to the ground in the 
fall, but their roots must be hardy enough to stand the winter 
freezing. There are a few tender perennials, however, such 
as the dahlia, canna, and gladiolus, that are among our most 
popular plants. These have fleshy roots or bulbs that are 
dug up in the fall and taken to a place of safety for the winter. 
F 
_... Cosmos ae ; - CALIFORNIA Poppy 
Another requirement that a perennial must meet is that 
it shall blossom before the autumn frosts. Many kinds 
require too long a growing season for our northern states, 
and would not blossom here even if we could carry them 
through the winter. © 
Planting Perennials. — The most desirable perennials 
for the northwest are planted as follows: 
1. Sow the seeds of the following early in the summer in a re- 
serve bed, then early in the fall, or the next spring, transplant 
