IRISH GARDENING 



VOLUME VIII. 

 No. 84 



Edited by C F Ball 



A MONTHLY JOURNAL DEVOTED TO THE 



ADVANCEMENT OF HORTICULTURE AND 



ARBORICULTURE TN IRELAND 



FEBRUARY 



»9'3 



Some Californian Irises* 



By W. R. Dykes. M.A., Charterhouse, Godalming. 



LIBRARY 



NEW YOR', 



botanica... 



QARUh. 



Between the Pacific coast and the 

 Rocky Mountains there is found a 

 well-marked group of Irises to which 

 the name Californian may he not 

 inconveniently applied. Its members 

 are perhaps better suited to the 

 climatic conditions of Ireland than 

 those of any other division of the 

 genus, for even in England the foli- 

 age of several of the species remains 

 green throughout the winter, unless 

 the frosts are exceptionally severe. 

 Moreover, the slender wiry rhizomes 

 do not seem to demand that baking 

 by the sun in summer which is 

 almost essential to the well-being of 

 those species, whose rhizomes are 

 large and fleshy. 



The reason why the Irises that 

 form this group seem to be compara- 

 tively little known lies in the fact 

 that they do not lend themselves 

 easily to transplantation. The slen- 

 der rhizomes send out few root-fibres 

 and the plants are therefore slow to 

 establish themselves in new quarters. 

 In addition to the paucity of the root-fibres 

 another difficulty lies in the shortness of the 

 period during which they are formed. If the 

 plants are torn up in autumn, root-growth will 

 be found to have entirely ceased, and the plants, 

 making no attempt to establish themselves, in- 

 variably perish. It is only while leaf -growth is 

 active, between March and early September, 

 that transplantation has any chance of being 

 successful. 



Fortunately all the species set seed readily, 

 er ^and young plants when put out into the open 

 •—ground in summer soon grow to flowering size. 

 ^The soil should be light and relatively rich in 

 }>. humus, but care must be taken that it is free 

 07 from any considerable proportion of lime. 

 r^ With regard to the species that form the 

 <C group it is jDossible to recognise two sub-divisions, 



of which the best known examples are I. longi- 

 petala and I. Douglasiana. Of these the former 

 is only found along the Californian coast in the 

 region of winter rain and heavy sea mists in 

 summer. The stems rise to the height of two 

 to three feet, and usually bear only one head 

 of flowers, from which, however, emerge in 

 succession as many as four or five blooms. The 

 large falls are conspicuously veined with deep 

 purple on a white ground, while the oblong 

 standards are of a uniform pale blue purple 

 colour. They are of a curious and characteristic 

 shape, having a square, blunt upper end with 

 a wide and deep indentation at the centre. The 

 foliage is of a deep green, somewhat stiff and 

 nearly as long as the stems. Moreover, the 

 plants begin to grow in the autumn, sending up 

 their new growths before the old leaves have 

 withered entirely away. Accordingly they are 

 practically evergreen. 



Differing from I. longipetala, chiefly in its 

 habit of growth, there is a closely allied species 

 that occurs further inland, and which behaves 

 as a mountain species by losing its foliage 

 entirely in the autumn and lying dormant until 

 the spring. The leaves never attain the length 

 of those of I. longipetala, and are always con- 

 siderably shorter than the stem. The flowers, 

 however, except for being somewhat more 

 slender, are indistinguishable from those of that 

 species. This is the plant to which Nuttall 

 gave the name of I. missouriensis, and it is 

 necessary to distinguish it carefully both from 

 I. longipetala, of which it is apparently only a 

 sub-species, and from another plant to which 

 Nuttall gave the name of I. montana, although 

 it is uncertain whether he ever actually published 

 any description of the plant. Fortunately his 

 original specimens both of I. missouriensis and 

 I. montana are still preserved in the British 

 Museum, and there seems little room for doubt 

 as to their identity. I. montana differs from the 

 two species already described by its lanceolate 

 and not truncated standards, and by the fact 



