Monday, January 8, 2018

William Mohr - A Brief Life But Enormous Influence on Iris

by Jean Richter

The San Francisco bay area has produced a number of important iris hybridizers. In my most recent blog (October 30, 2017), my subject was one of the earliest bay area hybridizers, Sydney B. Mitchell. One of Mitchell's close associates was an equally important hybridizer, William Mohr, whose work Mitchell carried on after his untimely death in 1923. Had Mohr not passed away at the age of 52 after only ten years of hybridizing work with iris, he undoubtedly would have become one of the most well-known iris hybridizers of his era.

      Sacramento (Mohr-Mitchell 1929)

William Mohr's father Cornelius Mohr was a German immigrant to the U.S. who, after leaving his job on a whaling ship in San Francisco, settled in the nearby Mt. Eden area (now known as Hayward) in the 1850s. Cornelius bought a grain farm from the Castro family (who had large holdings in the area via Spanish land grants prior to California's acquisition by the U.S.). His son William Mohr was born on the farm in 1870. Cornelius died in 1878, and after coming of age William took over the farm operations. He diversified the farm's holdings, adding row crops such as tomatoes and sugar beets in addition to wheat.  At the time of his death his holdings were 400 acres, most of which were rented out to other vegetable growers. He kept 60 acres to grow his strains of wheat and barley, and had two to three acres near his home for his flower garden, which was varied and extensive. He hybridized many other flower varieties in addition to iris, including daffodils, primrose, tulips, and clematis.

William married Alfreda (Frieda) Mohr, and they had a young daughter named Marion in 1913.

When William Mohr began his hybriziding work with iris, he first worked with the common tall bearded iris of the day, but soon began working with tetraploid iris species such as Iris mesopotamica and cypriana to introduce larger flowers and better branching into his hybrids. He also began working with the aril species oncocylcus and reglia, and used mesopotamica also in these crosses. He hybridized a very large variety of iris, including all the bearded classes, aril-bearded hybrids (arilbreds), spuria iris, Siberian iris, and Pacific coast iris.

  Iris mesopotamica

In his hybridizing work he was guided by extensive correspondence with early hybridizers Grace Sturtevant and Dr. Samuel Stillman Berry, and particularly by Sydney B. Mitchell, who lived just fifteen miles away. Describied by Mitchell in his obituary for him as a shy, retiring, and humble man, Mohr was quite reluctant to name and introduce his creations despite their quality. One early success was a cross of mesopotamica with the tall bearded iris Juniata (Iris pallida ancestry) which produced Conquistador (Mohr 1923).

 Conquistador (Mohr 1923)

A great interest in the last few years of his life was producing a larger yellow iris. He crossed yellow Iris pumila with mesopotamica and Iris trojana, seedlings which eventually resulted in varieties such as Alta California (Mohr-Mitchell 1931) and California Gold (Mohr-Mitchell 1933).

 California Gold (Mohr-Mitchell 1933)

He produced a number of large white seedlings, including the variety eventually named Purissima (Mohr-Mitchell 1927). I have a picture of this iris in my Mitchell blog, and here reproduce a picture from the 1938 bulletin of the British Iris Society, showing an enormously tall clump of Purissima next to the then-president of the BIS, Geoffrey Langton Pilkington (who as I understand was not a small man).
Purissima (Mohr-Mitchell 1927) with BIS President Pilkington

Mohr also had great interest in plicatas, and a number of his best plicata seedlings were  introduced after his death. Mitchell chose California place names for a number of Mohr's iris (e.g. Sacramento, the first picture in this blog), and below are two of Mohr's most famous plicatas, San Francisco (Mohr 1927), the first Dykes Medal winner, and Los Angeles (Mohr-Mitchell 1927).

   San Francisco (Mohr 1927)                   Los Angeles (Mohr-Mitchell 1927)

Mitchell named one of Mohr's seedlings for his wife Frieda:

Frieda Mohr (Mohr-Mitchell 1926)

Mohr also named an iris for his daughter Marian. Sadly, as far as I know this iris is no longer extant. If it could be found again, it would be a wonderful addition to his iris legacy.

Photo of Marian Mohr (Mohr 1923) and its namesake (from the 1923 AIS Bulletin)

In 1923, William Mohr, his wife Frieda, and daughter Marian were driving with three neighbors when they encountered a parked truck full of produce. With the large truck in their way (and no rail crossing gate) they did not see the oncoming mail express train which collided with their car, killing everyone except Marian, who was seriously injured but survived. After recovering, Marian went to live with her mother's parents in Iowa, but returned to the Bay Area to attend the University of California, where she met her husband Jeryl Fry. Together they worked her father's farm, and when that became too difficult with the encroaching city (the original farm is now on the site of Chabot  College), moved the farm activities to the San Joachin Valley, where it still exists today as the Mohr-Fry Ranches. Marian lived to the great age of 94, passing away in 2007. She and her husband are buried in the family plot (with William and Frieda Mohr) at the Mt. Eden Cemetery in Hayward.


After Mohr's death, Sydney B. Mitchell took his seedlings into his care, and began introducing his best varieties and working further with his stock. Mohr's best arilbred seedling and greatest pride, a cross of tall bearded iris Parisiana and aril species Iris gatesii, which had been shown in 1923 prior to his death at an Oakland iris show, was named by Mitchell as William Mohr.

William Mohr (Mohr 1925)

Despite his brief time in the iris world, William Mohr left a great legacy of iris, both bearded and arilbred. His influence is particularly evident in the arilbred iris, where it has been a naming convention for some time to incorporate Mohr into arilbred iris names. The AIS name registry lists over 100 iris names that include Mohr, the vast majority of which are arilbred iris. A few examples include Elmohr (one of whose parents is William Mohr), the winner of the 1945 Dykes Medal.

Elmohr (Loomis-Long 1942)

Another is Lady Mohr, introduced by Mitchell associate Carl Salbach, which also has William Mohr in its lineage.

 Lady Mohr (Salbach 1943)

A further honor accorded to Willliam Mohr is the William Mohr Medal, which is awarded by the AIS each year to the best arilbred iris of 1/4 up to 1/2 aril ancestry.

Despite the depth of William Mohr's influence on iris, one can only wonder what would have been if he had not left us so soon in his hybridizing career. What are your favorite William Mohr iris?

I am greatly indebted to my wife Bonnie Petheram, whose research at the Hayward Historical Society and the Sydney B. Mitchell papers at the UC Berkeley Bancroft Library form the basis of this blog, along with Sydney B. Mitchell's obituary of Mohr from the 1923 AIS Bulletin and historical material from the Mohr-Fry Ranch.