(1922) Regeliocyclus by van Tubergen
The Garden p.410, August 19, 1922
Some little time ago ( The Garden June 24, page 307
), you published a photograph showing one of the beds of the Regelio-cyclus Irises as grown at my Zwanenburg Nurseries. Judging from the poor and disappointing results the Oncocyclus or Cushion Irises mostly give, some people are only too ready to think that the Regelio-cyclus behave in the same way. Much already has been said in the columns of The Garden by enthusiastic amateurs, who reported their experience with these Irises, stating that they were quite satisfactory and flowered well for years in succession and I once more venture to bring this topic to the front. Our Dutch climate is by no means so mild and sunny as is sometimes believed ; we had a truly arctic, inclement winter, the ground in our garden was frozen more than 1 ½ ft. deep and our summers are mostly cool, with more cloudy days than bright sunshine. Notwithstanding these facts the Regelio-cyclus Irises, which I have now grown for more than a quarter of a century, always do well and flower very profusely, as the photograph clearly showed. It is no exaggeration to state that they flower more freely than the common Bearded Iris, which certainly give a mass of bloom, but only if they have been left untouched for some years ; transplanted rhizomes generally want a year or more to get established. The Regelio-cyclus group, which requires transplanting every year, gives a wealth of flowers the first season after being planted, coming into bloom at a period when all the tall Bearded varieties are only just showing buds.
It may be that their success here is partly due to our porous, sandy soil, full of lime, but on the other hand cold, wet, heavy soils are just as unsuitable to the ordinary Bearded Irises and anyone who has a warm, sheltered garden in good cultivation, so that he can grow the Bearded Irises well, can safely try the Regelio - cyclus varieties.
Visitors to the Chelsea Show had the opportunity of seeing great quantities of these flowers, English grown, and cut from the open ground only the day before the opening of the Show, which proves that they do not want the " favourable " climate of Holland to develop well.
Readers of The Garden who are not yet acquainted with the origin of this class and wonder why the Regelio- cyclus class always does well, as compared with the capricious Oncocyclus group, must not overlook that they have been saved from varieties of the various Regelia Irises (Korolkowi, Leichtlini, vaga), crossed with the best forms of the Cushion Iris (iberica, Lortetii, Susiana). The former never give any disappointment, forming in one season big clumps with many flower stems.
The progeny of these crosses, to wit, the Regelio-cyclus group, have inherited the free-flowering qualities of the seed parents, as well as the noble shape of flower which distinguishes all the pollen parents.
Culture may be briefly summed up as follows: select a warm, sheltered spot in the garden, for preference at the foot of a south wall, and work it deeply to ensure perfect drainage. If the soil is poor, mix a fair quantity of old pulverized cow dung in it ; if the ground be heavy, use plenty of sharp silver sand and surround the rhizomes with it. This will facilitate the formation of roots. Soils that are destitute of lime must be mixed with finely crushed old mortar. Plant about the middle or end of October and cover the rhizomes to a depth of about 3ins. in heavy soils, lin. more in light soils. Carefully spread out the fleshy roots attached to the rhizomes without huddling them together.
Where the soil is on the heavy side, plant, if possible, on a slightly raised bed, which will allow all superfluous water to drain away easily in winter. As these Irises are hardy, they require little protection in winter, but to prevent the soil getting beaten down by continuous heavy rains, a covering of fir boughs will suffice to keep the soil soft and manageable. About the middle of July, as soon as the foliage shows signs of turning yellow, lift the rhizomes, leave them in the open air for about three or four days to ripen off thoroughly, cut the foliage to about 4ins. from the crowns and shorten the roots a little. The rhizomes are then stored away in an absolutely dry, rather warm place (a shelf in a vinery is a capital spot). until planting time comes round again. If necessary the clumps may be divided then.
The variety Polyhymnia, of which I send a picture, is one of the best of my recent seedlings ; it is the result of a cross between a specially large flowering strain of Regelias, found by my collector some years before the war in Bokhara, and some of the best Oncocyclus forms. These flowers are much
superior to the original Korolkowi varieties as introduced by the Russian botanist. Dr. Regel of St. Petersburg, and crosses between this strain and the Oncocyclus have given remarkable results.
The variety Polyhymnia has stately stems, 20 inches tall or more, and bears uncommonly large flowers of noble Oncocyclus shape, with well rounded petals of a delicate creamy white, netted and veined all over with pinkish brown.
Holland. C. G. van Tubergen, Junior
For more information on historic Irises visit the Historic Iris Preservation Society at