Monday, November 25, 2013

The Missing Class - Dwarf Siberians

By Bob Hollingworth

There is no official definition of “dwarf” for Siberians; such a class does not exist. So I’m creating my own here and saying that anything that typically blooms at 15” or less could be considered a dwarf. That’s about half the height of the average Siberian bloom. Such plants have their own distinct personalities and have a special place towards the front of plantings, so you might think they would be common, but they are not. Dwarf genes are there, so that isn't the major reason for their comparative rarity. Perhaps the lack of a specific size class for dwarfs discourages hybridizers since these petite plants are less imposing than the standard sizes and tend to get overlooked when it comes to awards. This would not happen if we had a dwarf or even a median class for Siberians.

In general, the requirements for a good dwarf Siberian are the same as those for the bigger brothers – attractive flowers, placed so they are viewable separate from foliage, good vigor, and flowers appropriately sized to maintain the balance between plant and flower, which means smaller flowers (2-3 inches across). An example that seems to violate these principles in terms of flower placement and size is the recently described I. sanguinea tobataensis from Japan. Actually it has been known there for a considerable period of time but because of its peculiar flowering habit was not considered to be a Siberian. As you can see, the flowers are full size and held on stems 4-6” high. Since the foliage is 12-18” high they do not present themselves well. In other words these are normal flowers on a very short stem. So this seems to be more a curiosity than an ideal dwarf plant, but one that may be of interest to a hybridizer looking for short Siberians genes.

I. sanguinea tobataensis
A plant that better meets the above requirements is an old favorite, I. sibirica nana alba (an unfortunate name since it is more likely a sanguinea) which flowers at 12-15" over short, broad foliage. It’s origins are murky, being first listed by Perry in 1940. It once graced many gardens, but I haven’t seen it recently. Does someone out there have it still? I expect it has not disappeared because it was a capable grower.

I. sibirica nana alba (Photo courtesy of Greg McCullough)
Another cultivar perfectly fitting the non-existent dwarf class is Currier McEwen’s “Baby Sister” (1986, 6”).

"Baby Sister" (McEwen, 1986:  Photo courtesy of Jim Wilson)
The very small scattering of current “dwarves” in commerce seem to have often come about by accident rather than design e.g. Steve Varner’s flat, lavender and cream “Precious Doll” (1988, 12-14“) comes from parents that are not themselves short, as does the yellow amoena “My Little Sunshine" (Schafer-Sacks, 2012, 15").
"My Little Sunshine" (Schafer-Sacks, 2012)

The only person I know of who is currently focusing on breeding dwarf Siberians is Bill Dougherty in Minnesota. His “Summerchase Advent” (2007, 10") derived from “Baby Sister” is a fine dwarf white. You can see some of his more recent dwarf seedlings on his blog http://summerchasegardens.blogspot.com.

"Summerchase Advent" (Dougherty, 2007)
I make a cross between short irises once in a while, but without a highly focused program. Here’s our 05R10B2, a seedling from “Precious Doll” and blooming at 12-14”,  that is being evaluated along with some siblings for maintenance of dwarf form and vigor. One hazard of breeding for dwarf forms is that sometimes they grow up and out of “class” with time or in different locations. This was often noted by Currier McEwen who suggested that some of his small ones should be lifted and divided every few years to preserve their diminutive size. However, the ideal dwarf iris really should not need this to maintain its miniature characteristics.
Hollingworth Seedling 05R10B2
In 1981, Currier in his “Siberian Irises” commented “there is a particular need for more miniatures with small flowers on low plants in the full range of colors and forms.” This is just as true over 30 years later. The potential to achieve this is there and advances could occur quite rapidly. It would be an excellent hybridizing goal waiting for someone with limited space and time, and a desire to create something that barely exists at this time.

If anyone else is breeding dwarves as an objective, it would be interesting to know  Please post a comment below.