1910, Some Californian Irises by Dykes

The Gardeners' Chronicle p. 57, July 23, 1910


NOTES ON IRISES.

SOME CALIFORNIAN IRISES.

The various species of Iris native of the Western States of America seem to be well known and less generally cultivated than they deserve to be. The chief reason for this neglect appears to be that they do not lend themselves to the nurseryman's habit of moving all herbaceous plants in the autumn. If the plants are uprooted then, the more delicate of these species invariably die. They are somewhat erratic in their behaviour at any time, but, if treated carefully, they may be moved with very reasonable success at any time from April til early September, though, by preference, I should choose the earlier part of this period for the operation. By careful treatment is meant that the young root-fibres must not be ruthlessly trimmed off after the neat fashion in which Iris rhizomes arrive from Holland, for the slender rhizomes send out comparatively few of these fibres, and if these few are mangled, the plant stands little chance of re-establishing itself in new quarters. These Irises are best suited in a light soil that is free from lime and rich in humus.

It is a curious fact that American Irises seem to go in pairs, the individual members of which are, in most ways, almost identical, though their other characters are so distinct that we cannot group them together as one species. Of such pairs, I. bracteata and Purdyi. I. longipetala and missouriensis. I. Watsoniana and Douglasiana, I. hexagona and hexagona Lamancei are examples, though the two latter are, of course, natives of the Eastern States.

I. bracteata is one of the most beautiful of ail Irises. It derives its name from the fact that its stem is clothed in short, leafy bracts, and its evergreen habit is certainly a point in its favour. The flowers are yellow-veined conspicuously, and yet delicately, with a colour that comes very near to crimson, while the deep green, glossy leaves set off the flowers to great advantage. I. Purdvi is very similar. The leaves are rather narrower and shorter, but the flowers bear the same crimson veins on a yellow ground, although, in this case, the shade is a little lighter. In both species, the pointed falls are held horizontally, and the only real difference lies in the fact that, in bracteata, the perianth tube is very short, while in Purdyi it is nearly 2 inches in length. The plants are obviously different when growing side by side, and yet it would be very difficult accurately to define the difference between them if it were not for this distinct feature of the length of the tube.

I do not know of any record of other hybrids of bracteata, but this year I have had in flower here a dwarf plant which bore six or seven stems, and beautiful pink flowers of the characteristic shape of bracteata. The pollen parent I cannot give, as the seed parent would seem to have been fertilised naturally. It was growing in close proximity to both Douglasiana and tenax, and I incline to think that, to judge from the dwarf, somewhat spreading habit of the foliage, the pollen must have been that of Douglasiana. However that may be. the hybrid is certainly far more floriferous than its mother, and a delightful plant for some sunny corner in the rock-garden.

I. Hartwegii is one of those species which catalogues describe as of botanical interest, meaning, of course, that they do not wish to be uncharitable to any plant. The small flowers are of a pale straw colour, and two or three are produced on a slender but wiry stem. 4 or 6 inches long. My plants are growing where the seeds were sown in the open, and they are apparently quite hardy, at least in a light soil. They have flowered well both last year and this, and I hope they will consent to give me a fresh stock of seeds before any evil fate overtakes them.

I. chrysophylla, from Oregon, looks a picture of ill-health, and yet. since it flowers annually, I am beginning to think that its yellow leaves are enough to distinguish it from macrosiphon, with which it agrees in many ways. The stem is short, but the flowers are borne upon a long tube over 2 inches in length. They are of a creamy-white, with a few golden veins in the centre of the tails that seem to sparkle in the sun.

I. tenax is so called because of the wiry fibres of its leaves, which the Indians used to twist into twine of considerable strength. The stems rise well above the leaves, and bear comparatively large flowers, which may vary in colour from the palest pearly-grey, through delicate shades of mauve, to a deep. rich, claret tint. This really valuable plant suffers, I believe, from a note as to its cultivation in a certain popular book on the Iris, which describes it as thriving In peat kept moist with Sphagnum in partial shade. Under these conditions, my plants certainly did not thrive, but in dry sand, in a sunny position, they thrive amazingly and flower well.

For some time. I have been trying hard to solve the mystery of the longipetala. missouriensis, tolmeiana group, but only become more and more puzzled, and must obtain more material before coming to a definite conclusion. The examination of a large number of herbarium specimens collected in different localities has not thrown much light on the subject; but I incline to think that what was first described as longipetala has deep-green leaves of lax, almost evergreen habit, longer than the stem, which always bears more than two flowers on pedicels of unequal length, while missouriensis was applied to an earlier flowering plant with somewhat yellow-green leaves, which are more or less erect at flowering time, and distinctly shorter than the stem, which bears only two flowers. This theory, however, received a shock this year, when a batch of seedlings raised from Californian seed, and having the foliage of missouriensis, produced the inflorescences of longipetala. It is possible that the seed was from plants that had accidentally become cross-fertilised; unless this was the case, it would seem almost impossible to keep up any distinction between the two species. I am endeavouring to raise a second generation from these plants, and the results ought ultimately to throw some light on the question of the validity of the two names.

Iris macrosiphon I have never yet had in cultivation, but from all accounts, and to judge from herbarium specimens, it must be a desirable plant. It varies very much in colour, and is readily distinguished by the long (2 to 3 inches) tube.

I. Douglasiana and Watsoniana are obviously very similar, if not merely local forms of the same species. Both have practically evergreen leaves, with pinkish base, that are at their lest in winter; but while those of I. Douglasiana are narrow and lax, those of I. Watsoniana are broad and stiff, and spread in almost horizontal, fan-shaped tufts. A number of seedlings that I have raised here from plants of uncertain origin seem to show that these characters in the foliage are transmitted unchanged, but the plants are in other respects so similar that they hardly deserve to rank as more than subspecies. The colour of the flowers is extremely variable. It may be a deep rich violet with white veinings on the upper part of the blade of the fall, or these markings may be almost wholly absent. Other plants bear flowers of a pale lilac or lavender shade, and yellowish examples are not unknown. One fine large-flowered seedling has almost white flowers, with a faint tinge of lilac and some yellow at the throat, while another is heavily veined with violet on a silvery-white ground, producing a flower not unlike a small I. longipetala. Such seedlings flower-in one or two years at the most from the time the seeds germinate, and it may be that this fact has only to be more widely known than it appears to be to induce many gardeners to embark on the fascinating pursuit of raising Irises from seed. W. R. Dykes, Charterhouse, Godalming.


For more information on historic Irises visit the Historic Iris Preservation Society at

-- BobPries - 2014-11-19
Topic revision: r1 - 19 Nov 2014, BobPries
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