CHOICE PLANTS FOR ROCK GARDENS 151 
and the seedlings should be kept growing steadily through 
their first winter in a greenhouse just sufficiently warmed 
to keep out frost. 
Ir1s.—This is another of those wonderfully rich and 
varied families of plants that may well provide material 
for a comprehensive volume, but which the cleverest of 
writers can never adequately describe when bound by 
narrow limits of space. Even when we dispense with all 
the large strong-growing types and species that are rightly 
considered border plants and not rock plants, and eliminate 
those that belong to the water and bog garden, confining 
ourselves rigidly to the smaller kinds for which the rockery 
is the ideal home, we still have a list of species and their 
varieties that to name even, without enlarging upon their 
merits and cultural requirements, would require too great 
a space for our present possibilities. Nor is it perhaps 
desirable that in a work of general character written prin- 
cipally to aid the beginner and novice who seeks to acquire 
knowledge that will assist in forming and cultivating a 
collection of rock plants, an attempt should be made to 
wade gradually through the whole of this extensive family, 
for although for the most part Irises are quite easily grown, 
there are some types and species that are more exacting 
and somewhat difficult, and these are better left until 
study and experience enables the amateur to extend his 
attention to them with some degree of confidence. 
For the ordinary positions on the average rockery, or 
in the alpine bed of a small garden, the pumila group 
may well be among the first to be installed. Of dwarf 
stature, the flower spikes rising only 3 or 4 inches from the 
