UNIVERSITY OF ARIZONA 
TUCSON, ARIZONA 
DEPARTMENT OF BIOLOGY 
J. J. THORNBER August 11, 1914. 
J. G. BROWN 
IRISES IN THE SOUTHWEST 
The Iris or flag, Fleur de lis of the French, is among the oldest of our 
cultivated flowers; its name signifying “rainbow” was given to it by the 
Greeks. The Iris is related botanically to Orchids on one side and to the 
Amaryllis and Lilies on the other. It is a favorite flower with the Japanese. 
Irises constitute one of our largest groups of hardy perennial flowers; 
there are in cultivation now more than 1 00 species, with varieties almost too 
numerous to mention. When once established, an Iris bed should not be 
disturbed any more than is necessary, since ordinarily the plants do not blos¬ 
som well the first year after being set. 
Because of their general hardiness, and especially the drought resistant 
qualities of a large number of them, particularly the German Irises, they are 
admirably adapted for planting in southwestern gardens. There are few 
flowers that are as uniformly successful in Arizona, with our wide range of 
growing conditions, as the Iris. They can endure some alkali, strong light, 
thrive in heavy or light soils, grow with much or little irrigation and endure 
prolonged drought and heat. With their surface growing rhizomes they can 
even tolerate poor drainage. To be moderately successful, they require only 
the most ordinary culture. On account of the ease and success with which 
they grow, they should find a place in every garden. It is interesting to 
know that a number of rare Irises from Palestine and Syria which are grown 
with difficulty in the Eastern states, blossom and come to perfection in the 
mild climates of Arizona and California. 
The writer knows of plants that have grown for several years on dry 
Arizona mesas with only the scant rainfall and the occasional flood water 
that collected in the basins surrounding them. In the heavy red clay soil 
in the cemetery of one of our larger Arizona mining towns. Irises are much 
planted and succeed beyond expectation. When established there, they 
grow and blossom year after year with little care, and they have come 
to be known to the children as “Easter Lilies.” I know of no other flower 
that would thrive so well under the same trying conditions. 
Irises are used to advantage in many kinds of planting, including mass¬ 
ing, setting along borders of walks and drives, and also for naturalizing in 
back yards, in woods and along brooks. With their showy flowers and strict 
habit of growth, they are excellent for formal bedding and they lend them¬ 
selves well to artistic effects. In addition to Irises heretofore mentioned 
should be noted the several dwarf Irises which are splendid for low borders, 
and the Spanish and English Irises, the two latter bulbous species indigenous 
to Spain. 
It is only within the last few years that Irises have begun to receive the 
attention from florists they merit. The large number of varieties, their ar¬ 
tistic qualities and their wide range of color insure for them a permanent 
place in our gardens as well as in the heart of the amateur gardener. After 
several years’ experience growing small lots of Irises shipped from various 
sections of our country, those grown in California and the Southwest have 
been found to be larger plants and to do better than those from the Eastern 
states. This is not surprising, however, since it is the rule with most other 
plants, and whenever possible locally grown plants should be purchased. On 
this account, the writer recommends with pleasure Iris plants grown by the 
Dean Iris Gardens as being healthy plants that are most certain to succeed 
under our trying Arizona conditions. 
J. J. THORNBER. 
