1664 



IRIS 



IRIS 



arise clusters of tall branched flower-stems 2 to 3 feet 

 in height. /. sibirica has several varieties ranging in 

 color from deep blue to white. These, with the addi- 

 tion of /. Wilso7iii, make it possible to have tall clumps 

 of blue, white, and yellow irises of the sibirica type. /. 

 sanguinea, which has the flowers partly hidden among 

 the leaves is less ornamental than /. sibirica, in which 

 the flowers are raised high above the leaves. I. Dda- 

 vayi is a blue-flowered species which flowers in July 

 when most other irises have passed. The plants of this 

 group all thrive best in rather moist situations. Of the 

 spuria group, only the tall ornamental forms closely 

 alhed to I. spuria are considered here. The most com- 

 monly cultivated forms are /. spuria, I. halophila, 

 better known as /. Gucldenstsedtiana, I. orientalis, I. 

 Monnieri and /. aurea. These differ from each other 

 only in minor characteristics such as color and shght 

 modifications in the shape of the segments. They are 

 frequently all regarded as varieties of a single type, /. 

 spuria, but for horticultural purposes it is more ser- 

 viceable to treat them as separate species. Besides 

 those forms which may be said to approach specific 

 rank, innumerable minor varieties exist in the group. 

 The color of the flowers ranges from blue in /. spuria to 

 bright yellow in I. Monnieri and deep yellow in /. aurea. 

 In /. orientalis the flowers are pale yellow bordered with 

 white. The proportion of white and yeUow varies much 

 in different specimens. The plants of this group are 

 taU and stately with leaves 1 to 2 feet long, drooping 

 gracefully above. The flower-stems usually rise high 

 above the leaves, and bear two to three heads of flow- 

 ers. Those on the lateral branches are held close to the 

 main stem so that the whole inflorescence has the 

 appearance of a spike. The stems are usuaUy 2 to 3 

 feet high. Those of /. aurea are said to grow to a height 

 of 5 feet in Cahfornia. Some of the species are natives 

 of swampy regions and consequently thrive well in 

 wet places. All grow well, however, in almost any 

 situation. 



4. Dwarf irises. — Dwarf irises occur in several sub- 

 genera but the best-known and most commonly culti- 

 vated forms are the dwarf European pogonirises, 

 including /. pumila, I. pseudo-pumila, I. biflora, and /. 

 Chamsnris. These are remarkable for their numerous 

 color varieties, which range from pale yellow to lilac, 

 blue, purple, and very dark red. Most of the forms in 

 cultivation are varieties of /. pumila and /. chanise- 

 iris, but many of the garden forms which pass as 

 varieties of /. pumila are derived from /. Cham^iris. 

 I . pumila and /. Chamsnris are the most satisfactory of 

 the group, as the others are less hardy or less florif- 

 erous. I . arenaria, the Hungarian form of I . flavissima, 

 thrives well in dry sandy situations. The most common 

 dwarf forms among the apogon irises are /. humilis, 

 I. ruthenica and the American /. verna. Of these, /. 

 verna is the most striking because in all characteristics 

 of habit and growth it resembles a pogoniris but lacks 

 the beard characteristic of that group. /. cristata 

 and its close relative, or perhaps subspecies, /. lacus- 

 tris, are dwarf American forms belonging to the 

 subgenus Evansia, or crested irises. The dwarf irises 

 seldom grow over 9 inches high. They spread rapidly 

 by their creeping rhizomes and soon form large 

 patches. This habit makes them useful as border 

 plants. 



5. Oncocydus irises. — The oncocyclus irises differ 

 from other irises in several striking characteristics. 

 The seeds have a creamy-white aril nearly as large as 

 the seed itself. The stem is surmounted by a long, 

 unkeeled tubular spathe which reaches beyond the 

 top of the perianth-tube. The stem bears a single 

 flower, which in some species is of enormous size, com- 

 pared with the size of the plant. The segments, of 

 which the inner are larger than the outer, present a 

 most singular combination of somber colors. The 

 pecuUar colors are often due to the interlacing of num- 



erous very thin veins, usually blue or brown, on a white 

 or straw-colored ground. The most common shades 

 thus produced are beautiful sky-blue, Ught gray, and 

 brown to almost black. In some, all the segments are 

 colored nearly aUke, but in most species the inner and 

 outer segments are differently colored. The species 

 fall into two groups according to their geographical 

 distribution. With their distribution other charac- 

 teristics are curiously correlated. The species occurring 

 in central and eastern Asia Minor, Transcaucasia, and 

 the mountains of northern and western Persia are dwarf 

 slender species differing from each other by well- 

 marked characteristics. Those found -in Palestine, 

 Syria and Mesopotamia are tall, attaining a foot or 

 more in height, and resemble each other so closely that 

 they cannot be distinguished by any characteristic 

 except the color of the flowers. These apparently are 

 all varieties of a single species. In America the onco- 

 cyclus irises are not widely cultivated. The most 

 commonly grown form is /. susiana. Many hybrids 

 have been raised in Europe. For a monograph, see 

 Foster, Gn. 43, pp. 130-135. 



6. Bulbous irises. — About 20 species of bulbous irises 

 are cultivated in America. They are rather dwarf, 

 hardy and half-hardy bulbous plants, known chiefly for 

 the brilhant colors and strong contrasts, and for their 

 numerous flowers. The species most commonly found 

 in gardens are /. Xiphium, better known as /. his- 

 panica, and /. xiphoiiies or /. anglica. The latter is 

 probably the oldest iris in cultivation. See Foster, G. 

 C. II. 23, pp. 567 and 726, and Foster, Bulbous Irises 

 (1892). Heinrich Hasselbbing. 



The cultivation of irises. 



As will be seen by their distribution, irises are espe- 

 cially adapted by their hardiness to growth in our gar- 

 dens, though some forms, as the African, the Indian, 

 and the Oncocyclus species, need special treatment or 

 protection. In the main, the irises, from a cultural point 

 of view, are hke others of the various natural fami- 

 hes, mostly very good — not to say commonplace — 

 with a few decidedly inferior members. As there are 

 nearly 170 species of irises, with countless varieties, 

 they are interesting to the amateur coUector and 

 grower both for their variety and their general beauty 

 of flower. 



The hfe of iris flowers varies from three to six days. 

 They are fragile, but if cut before the petals unroll may 

 be forwarded to considerable distance without injury. 

 This is the only way, in fact, by which the florist can 

 market them. The botanists divide the irises into two 

 main groups, the bulbous kinds and those with rhizomes, 

 these groups being each divided by the varying charac- 

 ters of the more or less raised Kne in the middle of the 

 fall of the flower. This, of course, gives no clue to cul- 

 tural necessities or to time of flowering, two important 

 details in a garden. 



Considering the bulbous irises as a group, these are 

 all hardy without protection in the latitude of New 

 York city except /. Hisirio, I. alata, I. juncea, I. 

 palapstina, I. tingitana, I. Varlanii. 



In the order of their flowering, the reticulata group 

 is the earliest, /. Bakeriana and others starting into 

 flower as soon as released by frost, usually in February 

 or March. These are soon followed by the others of 

 this group, the largest-flowered member being /. his- 

 trioides. A peaty, sandy soil seems to be most accept- 

 able to this group, and no organic manure must be 

 given them. A location, if possible, where they may be 

 kept on the side of dryness in summer is desirable. The 

 culture of these, like that of all exotic plants in our gar- 

 dens, is, of course, tentative. If, on trial, they seem to 

 be happy and increase from offsets or buds, they may 

 remain in the borders indefinitely, but if during the 

 second season they show no gain, the bulbs should be 



