What is a Dwarf Bearded Iris? A Brief History of the Shifting Definition of the Class

In the beginning, there were no class definitions. The meaning of the term "dwarf bearded iris" was taken for granted, as all the ones being grown in gardens were similar in appearance and distinct from their taller relatives. If you were botanically inclined, you could turn to a reference like W. R. Dykes's The Genus Iris to get a list of dwarf bearded species, and safely assume that your garden dwarfs were hybrids or forms of those species.

The 1939 AIS Checklist attempted to be somewhat more helpful by giving a height range in addition to the list of species, setting the boundary between dwarfs and intermediates (which were stated to be hybrids between dwarf and tall bearded irises) at 17 inches. This doesn't make sense, though, if it is taken as a definition, rather than just helpful descriptive information. What if two of those dwarfs species were crossed and produced a hybrid over the limit? Or what if a dwarf and tall were crossed and produced a hybrid under the limit? Giving both a definition in terms of ancestral species and a definition in terms of height is inviting contradiction unless it is clear whether ancestry trumps height or vice versa.

Perhaps in recognition of this, the AIS adopted a new classification in 1947, based decisively on ancestry. A hybrid involving only dwarf species would always be a dwarf; a hybrid involving only tall species would always be a tall. A hybrid involving both dwarfs and talls would usually be intermediate, but might be deemed either dwarf or tall if that was the group it most resembled. Although this last provision was strangely vague, it at least allowed hybridizers to cross dwarfs amongst themselves and register the progeny as dwarfs, without worry about a height limit or other factors. This classification system was introduced at the same time as Walter Welch was organizing the Dwarf Iris Society and stirring up interest in dwarf hybridizing, so there may have been some impetus to clarify definitions for this reason.

In 1951, something happened that put the class definition under unprecedented strain. Paul Cook introduced the first three irises of the type we now know as SDBs, from crossing the tiny dwarf species Iris pumila with tall beardeds. As a dwarf x tall cross, a strong case could be made that these new irises were intermediates, and indeed that is how they were registered at the time. But they were no taller than many of the dwarfs being grown at the time, so this might seem a little inconsistent. Welch and the DIS focused attention on the presence of a small branch in most SDBs, asserting that a branch was disqualifying for being considered a dwarf. Oddly, the list of dwarf species that AIS had been printing and reprinting for many years included amongst the dwarfs Iris aphylla, which is copiously branched.

Recognizing that the future might hold even more examples of such "problem children" from newfangled hybridizing experiments, the AIS suddenly reversed itself in 1954, offering a classification based entirely on height, with ancestry deemed irrelevant. This makes sense in a world where parentages have become complex or uncertain. Height is something that can be established with a ruler. Now the boundary between dwarfs and intermediates was set at a rigid 15 inches, regardless of what species the plants had come from or what characteristics they had. Welch and the DIS refused to accept this definition, appalled at the thought of 15-inch branched "intermediates" masquerading as dwarfs! This caused a rift between the AIS and the DIS whose repercussions are still playing out today.

Other classification issues were percolating at this time as well. There were movements afoot to recognize the so-called "table irises" and "border irises" as separate from both TBs and IBs. A committee was put together to study all these issues and propose a solution. In 1958, the AIS adopted a classification that has remained in place (with minor modifications) to this day. The dwarfs were separated by height into miniature dwarfs and standard dwarfs, with the dividing line being 10 inches. The border bearded class was created for short TBs, and the miniature tall bearded class was created for the table irises. The DIS had no interest in any of these new classes, not even the SDBs, and so the Median Iris Society was formed with the mission of promoting the four new classes between MDB and TB. A peculiar quirk of this development is that standard dwarfs are considered medians, not dwarfs, in apparent contradiction with their name.

In light of this history, one can understand why the DIS has remained rather protective of the little irises under its charge, and reluctant to muddle the boundary between the dwarf MDBs and the median SDBs; the dividing line between the classes was later reduced to 8 inches, in part to protect the MDB class from SDB interlopers. It also explains the misgivings of many DIS members about merging with MIS, which has been suggested on a number of occasions. Any of the median classes might seem to have more cause to have its own society, given that they all have more new irises introduced each year than does the MDB class. Yet our history has set us apart, and perhaps it is the very fragility of the class in the face of the much larger (in numbers as well as stature!) median classes that inspires a certain connoisseur's devotion amongst us.

Tom Waters

January 2019

Unless otherwise noted, all text and illustrations copyright Tom Waters and all photographs copyright Tom or Karen Waters. Please do not reproduce without permission.