212 
The Garden Magazine, December, 1923 
ROOF IRIS (I. tectorum) 
A NOTHER Chino-Japanese species which does not seem to 
have been in Occidental cultivation nearly as long as 
I. japonica, yet because of its hardier constitution is a great deal 
better known in our gardens, is the Roof Iris, I. tectorum. This 
is stated to have received its name, both in the Latin and the 
vernacular, from the circumstance that in the Orient it is com¬ 
monly grown in the thatch on the roofs of houses. Indeed, 
some botanists claim to have traced the cultivation of this Iris 
by the Chinese back as far as the seventh century, and there is 
now grave doubt whether the Japanese plants, or even those in 
quite every corner of China itself, are truly indigenous in the 
country which they now seem to inhabit, or whether they are 
merely escaped garden introductions. 
As compared with the foregoing species, I. tectorum seems 
far less ethereal and its coloring more emphatic and less refined, 
and also it does not have the lush green foliage. The much 
larger flowers are of quite different outline, the sudden constric¬ 
tion of the petals at the base giving them a spidery effect and 
perhaps an even greater originality and picturesqueness than 
possessed by I. japonica. Furthermore they are far less evanes¬ 
cent, and this trait combined with their size and deep coloring, 
gives the plant a value in the garden for massing that is indeed 
unusual in an Evansia. The exact hue, it may be added, is 
near pleroma violet of Ridgway, with an irregular but pictur¬ 
esque splashing of haematoxylin violet. The characteristic 
crest in this species attains an extraordinary development, and 
is not only all slashed and fringed, but is principally white and 
so in contrast to the general ground color of the flower as to be 
very conspicuous. Like all the other Evansias, tectorum comes 
into flower much later than japonica, but the long season of the 
latter brings about a certain amount of overlapping. 
There is a pure white form. Iris tectorum alba, which I have 
not been so fortunate as to see in flower, but which is said to be 
among the most beautiful of all white Irises. Although Dykes 
long ago uttered a timely warning against the prevalent bar¬ 
baric misspelling of the name, the few nurserymen’s catalogues 
Flourishing in the thatch on roofs of houses in the 
Orient, “probably no Evansia is so easy to grow un¬ 
der so diverse climatic and cultural conditions,” its 
size and deep coloring (near pleroma violet of Ridg¬ 
way) making it particularly effective for massing 
gathered when there is a goodly number of buds just 
upon the point of bursting, a cut stem will last very 
well in the house also. 
The leaves are a fresh shiny green, quite unlike those 
of most Irises, and set off the delicate lilac of the blos¬ 
soms to excellent advantage. The actual tint of the 
segments is perhaps nearest to the pale wisteria violet 
of Ridgway’s nomenclature. Falls and standards are 
similar in tone, but the former are lightly veined with 
a deeper hue, and have each a vivid signal patch of deep 
chrome on a white ground margined in its turn with 
dots and splashes of soft bluish violet, all of which make 
up into a bit of color painting impossible to render in a 
black and white halftone illustration. The crestisviolet. 
In California the plant is very much of a shade lover, 
although I have found either the sun of early morning or 
of late afternoon to be an advantage rather than the re¬ 
verse. In the heavy red adobe of my California garden 
the plant has one provoking fault, however—that of 
continually trying to climb out of the ground, making 
much or all of the new growth above the surface and 
dying out below, so that one must ever be pushing the 
rhizomes back into the earth, or keep the bed replenished 
from the young offsets which are always arising from 
the tips of the slender running stolons pushed forth by 
the plant in every direction. In a lighter soil or one 
with more natural moisture, the plant might be more 
amenable to persuasion. 
THE BUTTERFLY-LIKE IRIS JAPONICA 
“In the Gulf States, perhaps, and certainly in the milder sections 
of our Pacific costal area, this species grows and flowers luxuriantly 
with a near minimum of attention”; color pale wisteria violet 
