Cultural Requirements 
Under the Aril Iris heading are some of the Iris World's outstanding beauties — the Oncocycli, the 
Regelias and their hybrids and derivatives. They are also among the most difficult to grow and propagate 
and are a constant challenge to the devotee. Although they have been formerly considered as temper- 
mental as a Prima Donna the rewards from pampering them have been sufficient to enslave any Irisarian 
worthy of the name. 
We have studied closely their requirements—soil, moisture and temperatures. We have grown them in 
raised beds out of doors, in pots and large boxes both in the greenhouse and in the open. We think we 
have learned more than a little about them. 
Practically all material written about their culture suggests the use of lime or limestone in the soil for 
they prefer a soil on the alkaline side. We who live in California particularly have been prone to confuse 
lime and alkalinity! They are by no means synonymous! Our soils and our water have an alkaline re- 
action—but in many cases it is caused by Soda—not lime! 
Recently there came into our hands a volume entitled ‘The Book of the Iris’ by R. Irwin Lynch of Eng- 
land and published in Edinburgh. The Preface, written by the author, is dated Dec. 31, 1903. Its wealth of 
knowledge and information is astounding to those of the present day who think the ‘Mohr’ family is the last 
word in the Oncocyclus section. 
This book among other things contains a table which was originally published in the Journal of the 
Royal Horticultural Society of 1901. It gives the results of an analysis of the soil in the Nursery of the firm 
of C. G. van Tubergen of Haarlem, Holland and also the soil of Palestine where there were Oncocyclus 
growing. The table is long and complex with little variation between the two soils until we come to Lime 
and Magnesia! The imported soil showed a content of 155.800 for Lime against 1.840 in the Nursery soil 
and 49.550 for Magnesia against 0.516 in each 1000 parts. 
The van Tubergen Nursery forthwith prepared several test beds 3’ wide and 24’ long in which was in- 
corporated different amounts of both powdered ‘marl’ and magnesia, with a rather heavy soil. The best 
results were obtained from a bed in which 44 pounds of marl and 19!/. pounds of magnesite were used. 
Plants in this test bed rooted rapidly and heavily, while the fans were a lush green in which no tip burn 
occurred. Bloom was extra heavy. This firm has continued over a period of many years to hybridize Regelias 
and Oncocyclus with considerable success. Mr. van Tubergen had stated at the time that a dolomitic lime 
_ stone would have been preferable for it contains both calcium and magnesium, but it was then unobtainable. 
After reading this account we were inspired by a new hope and immediately set about to correct our 
soil. Dolomitic Limestone is now available in a powdered form, which is most inexpensive, under the name 
of ‘Dolomite’. We worked in what we thought was the proper amount and watered heavily. Even this treat- 
ment of ‘little and late’ gave added growth to many of the varieties which we grow. Several have bloomed 
even later than would usually be expected. 
All orders for Aril Iris will have included a more comprehensive recommendation and instruction than 
can be included in this limited space for we are convinced that with the proper soil the Arils will cease to 
be a flower which only the expert can grow. Further, we will consider it a pleasure to correspond with any 
one where we can be of assistance. 
COhe Court of Iris 
MAILING ADDRESS: 
DISPLAY GARDENS AT THE COURT OF IRIS 
7931 E. Imperial Hwy. P. O. Box 606 
Downey, Calif. Bellflower, Calif. 
