Exploring the Mysteries of Bloom Season & Height: Siberians

By Bob Hollingworth

It's really quite strange that we have never standardized how we communicate the bloom time or height for irises, even though these are required characteristics in registering an iris with AIS.  

The situation of bloom time as it refers to Siberians is exactly like the bearded irises as described by Jim Hedgecock in his recent post. To me the registration should indicate when this cultivar blooms in relation to other cultivars in the class, hence the E, M or L designations, maybe with a V(ery) added to indicate unusual earliness or lateness.  However, clearly some hybridizers use these terms not to indicate peak bloom time but duration of bloom with the designation EML, meaning, I suppose, that it starts early and blooms throughout the season and not that it can start bloom at any time in the season (which is quite unlikely, since relative bloom time is quite reliable with Siberians).

'Who's On First' (Hollingworth, 2008)

'China Spring' (Bauer-Coble, 1999)

The introduction of  I. typhifolia to US hybridizers about 20 years ago moved up the bloom season for Siberians since these typically bloom 2-3 weeks before the more familiar sanguinea/sibirica hybrids (although a few sibiricas can bloom quite early too). So the meaning of Early has changed a bit with time.  Cultivars with some I. typhifolia genes will likely bloom well before the pack, such as 'China Spring' and 'Who's On First,' or Dave Niswonger’s “China” series.  

The season used to end for us when derivatives of Bill McGarvey's later whites including heritage from 'Esther C. D. M.' and 'Gull’s Wing' opened up, such as 'Hooked Again'  or 'Blushing Violet' . But I believe we may have a new winner for latest to bloom - 'Pool Party'. The last two years this has bloomed for us so late you wondered if it would ever open - after many early cultivars were already bloomed out. However, this may not be typical since 'Pool Party' is registered as an ML bloomer not VL. We don’t grow 'Worth the Wait' (Schafer-Sacks, 2002) or 'Last Act' (McEwen, 1985), but the names suggest that they should be very late bloomers too.

'Hooked Again' (Jim Copeland, 2006)

'Blushing Violet' (Hollingworth, 2005)

'Pool Party' (Cole, 2008)

Unfortunately, it seems that nothing is ever that simple and there are a significant number of Siberians that repeat bloom (mostly rather sparsely) a few weeks after first bloom. If the repeat bloom period is clearly separated by a flowerless period, it is easy to characterize, but a few irises stagger along between these two seasons and never seem to be entirely out of bloom for several weeks. This characteristic probably this led to the most convoluted registration I know ('White Prelude', McEwen, 1993) which is registered as VE-EML-VL & RE!

Whether to indicate the “repeat” bloom in the registration (and advertising) is a matter of judgment for the hybridizer – but if this happens most years and gives a display that attracts attention, it certainly is justified. There is a genetic basis for this tendency.   Nevertheless, the nature and environmental conditions that govern "continuous bloom" and "repeat bloom" are still quite mysterious. It also seems that some Siberians repeat bloom more readily in some regions than others, which makes their characterization even more difficult.

Height is in some ways a bigger problem, since here we are giving absolute values (e.g. 25 inches) rather than relative ones (dwarf, median etc.) and of course this is going to vary from year to year and from place to place as growing conditions vary.  

With Siberians a good clump will often have blooms at several heights - shorter around the outside and taller in the middle.  This gives a desirable bouquet effect as seen in the photos above.  So which height to choose? And then again, the flower stems elongate during the bloom period and may end up several inches taller on the last blooms compared to the first ones.

I expect different hybridizers use different methods to handle this variability. I generally record the height of taller stalks (ground to top of flower) for several years before introduction and use the tallest year as the registration height. Why not the average? Because this way seems to me to best represent the genetic potential (under ideal  growing conditions) of the variety. What does everyone else do?

'My Little Sunshine' (Schafer-Sacks, 2010) 

In fact, since there are no size classes for Siberians as there are with bearded irises, exact height is not critical and it would be just as good to have relative classes for height as we do for bloom time.  Dwarf, median, and tall are convenient, but that’s not how the current system works, in part because “dwarf” has a specific meaning in the bearded world that does not translate to Siberians. We do have irises that regularly bloom much shorter than most others  ranging from the old sibirica nana alba (which is actually a sanguinea in all probability!) to more recent ones like 'My Little Sunshine' that bloom at around 12-15 inches.  Compare this to the giants of the Siberian world at 48 inches or taller!  Let’s leave  with the thought that the long and the short of the Siberian iris world might make a good topic for a future post.

Exploring the Mysteries of Bloom Season & Height: The Historics

By Mike Unser

One of the first things anyone beginning to research historic bearded irises is confronted with is the often contradictory designations about the classification of varieties by size and/or bloom season. It is difficult enough to get an idea of these terms in just the bearded iris realm, but it is even more confusing when you realize that other species may conform to their own definitions. For the next several weeks we'll be exploring the different aspects of these topics here on World Of Irises, and I'd like to start by clearing up a little confusion for those new to historic bearded irises.

When the American Iris Society was first formed in 1920 one of the first major projects they instigated was a census of all the literature regarding irises, which was used to create a Checklist of all known cultivars to that date. This was a years long undertaking of Ethel Anson S. Peckham first published in 1929 and remains the premiere work of its type in irises. This, along with registering new cultivars, was an attempt to bring order to a chaotic situation, to sort out authentically named varieties from impostors, as well as to bring worthy varieties with correct names to prominence and to document their parentage in order to bring organized principles to the improvement of the genus. In 1939 a revised and updated Checklist was published that built on the earlier work and expanded it enormously. It is an invaluable tool for anyone interested in the history of garden irises, and we owe Mrs. Peckham a great deal of gratitude.

One of the first things one will notice when comparing current glossaries with the original checklist is that the designations for bearded irises fall into just three classes: dwarf (DB), intermediate (IB) and tall (TB). This continues into the 1949 Checklist. With the 1959 Checklist we finally see the classifications we are currently used to: the dwarfs have been split into Miniature Dwarf Bearded (MDB) and Standard Dwarf Bearded (SDB), IB is still there with some alteration, Miniature Tall Bearded (MTB) and Border Bearded (BB) are new, and with TB still at the end but not with the same in definition as before. Bob Pries wrote in a recent article in Flags:

TBs were defined in 1939 as irises over 17 inches tall and Dwarfs were up to and including seventeen inches. Of course the Dwarfs had not yet been split into miniature dwarfs and standard dwarfs. The median classes, of MTB, BB, and IB did not quite exist between 17 and 27½ inches. I say not quite because the talls of the time were also sorted by bloom time with the class of IB. But IB, or intermediate bearded referred to bloom time and did not have a sharp cut-off of 27½ inches.

And that is where the confusion mainly comes in - Intermediate Bearded originally referred to season of bloom, not height or size. The first crosses between dwarfs and talls resulted in varieties of all heights that mainly bloomed after the dwarfs and before the talls, and that is what was used to distinguish the different classes. In the 1950's the AIS instigated a further division and reclassification into the current model, using not only bloom time but height, bloom size and other attributes to determine how a variety was to be classed. Now, IBs need to not only bloom between the dwarfs and the talls, but have an ideal range for height, bloom size and other attributes as well. The dwarfs and talls have similarly been broken down into more specific classifications. In the early 1960's older varieties were reclassed in a new Median Iris Checklist to bring them into as close of conformity as could be determined to the new model.

All of these changing definitions can be very confusing for someone new to the history of irises to sort out, but once this basic timeline and 'definition drift' has been taken into account we can better make use of the published materials that are so important to the historic iris enthusiast.

The following are a few examples of some historic irises that have been reclassified from their original designations into our modern system of designation.

One of the most widely grown irises that has been reclassified is 'Sans Souci' (Van Houtte, 1854), one of the many sports of 'Honorabile', a variety with proven hardiness and a penchant for throwing out sports of its own. 'Sans Souci' had been classed as a Tall Bearded variety originally, but is now listed as a Miniature Tall Bearded. Oddly, 'Honorabile', to which it is identical in all respects but color expression and tone, was originally classed as an IB. All the sports in this family are now classed as MTBs.

'Titmouse' (Williamson, 1934), was originally classed as an Intermediate Bearded iris, but has also been moved to the ranks of the MTBs.

Grace Sturtevant's lovely little 'Tid-Bit' (1925) is an example of a variety formerly listed as a dwarf Bearded that has moved on up to MTB as well.

Three irises originally in different classes, now sharing the same designation. Is it any wonder folks get confused when researching historic irises? The new designations are not always a perfect fit, but they are the best we can do with varieties that were never created to conform to our current standards. In upcoming posts our other authors will explore how bloom season and height designations are treated in the median and tall bearded classes currently, as well as how these are classed in other iris species. Stay tuned!