Using Species in MDB Breeding, Part 2: Iris aphylla x Iris pumila

 by Tom Waters

This is the second of three posts on my experimenting with various species in breeding miniature dwarf bearded (MDB) irises. Here’s a quick recap: Most MDBs today are small selections created when breeding standard dwarf bearded (SDB) irises. I think there is value in creating a line of true-breeding MDBs: fertile plants that are MDB-sized and consistently produce MDB-sized offspring. Ideally, such a line would be compatible with SDBs (and MDBs from SDB breeding), so one could use all the wonderfully developed modern MDB and SDB cultivars.

Certain dwarf species and combinations of species are compatible with SDBs in terms of their chromosome configuration. One such species is Iris lutescens, and in part 1 I described my work with this species to date. In this post, I look at hybrids from I. aphylla x I. pumila and their usefulness in MDB breeding.

I. aphylla crossed with I. pumila produces fertile hybrids having a chromosome configuration that is compatible with SDBs. The MDB ‘Velvet Toy’ (Dunbar, 1972) is an early example of such a hybrid. We might also include Ben Hager’s MDBs from his aphylla-derived MTBs crossed with I. pumila as another variation on this basic type, although the MTBs have tall bearded and border bearded ancestry as well as I. aphylla.

S006-01
 I. aphylla x I. pumila

My own aphylla x pumila seedling, S006-01, is an interesting little plant. The flowers are purple and not particularly distinctive, but the plant is quite small, at around five inches in height. It also has a unique branching pattern. It has basal branching inherited from I. aphylla. The branch and the main stem are of equal height, and each is topped with a double-budded socket. The four buds open successively, so there is only one flower open at a time. This seems to me a very desirable trait to introduce into MDBs, but so far none of its seedlings have inherited it.

I have bloomed a number of seedlings from SDB ‘Eye of theTiger’ (Black, 2008) X S006-01. They were a carnival of different colors and patterns, but unfortunately, none had the daintiness I was looking for. This spring, seven years after I made the cross, a straggler bloomed that seems genuinely small and MDB-sized. I will keep an eye on it in coming seasons.

S028-44
Eye of the Tiger X S006-01

Realizing that I probably should be crossing this seedling with small MDBs rather than SDBs, I used ‘Dollop of Cream’ (Black, 2006) and ‘Icon’ (Keppel, 2008) for the next round.

The ‘Dollop of Cream’ seedlings had fairly nice form, some blue, some white. They bloomed near the boundary of the MDB and SDB classes, but I am hoping they may settle out on the smaller side when grown in normal garden conditions. I kept a blue one with small flowers to evaluate further.

Seedlings from 'Dollop of Cream' X S006-01

The ‘Icon’ seedlings are more exciting color-wise, in various shades of orchid with deeply saturated spot patterns and dark blue beards. I describe the color as “juicy”. Sadly, they produced hardly any pollen, and I couldn’t really test them as pod parents because they bloom earlier than anything else except the pure I. pumilas. I did get a scant 8 seeds from sib-crossing two of them, so we shall see. Again, height is rather marginal, near the boundary between MDBs and SDBs. I’m keeping them all in hopes that they may produce more pollen in the future.

Icon X S006-01

I do believe my I. aphylla x I. pumila seedling has the potential to bring me toward my goal of a line of true-breeding MDBs. I have seeds from it crossed with ‘Self Evident’ (Hager, 1997) and ‘Miniseries’ (Keppel, 2011).  And it will also be interesting to take this one more generation further and see what emerges.

Bearded Iris Species for the Garden

 by Tom Waters

Most of us are quite familiar with the gorgeous hybrid bearded irises grown in so many gardens around the world. Whether dwarf, median, or tall bearded, these irises are the great show-stoppers of the springtime iris parade. Every year, hybridizers introduce new varieties, so there is a never-ending stream of new colors, patterns, and flower forms.

But before hybridizers took an interest in irises - and that was scarcely more than 100 years ago - bearded irises in gardens were much like irises in nature. Yes, bearded irises are wildflowers in Europe and western Asia, where numerous different species grow on hillsides or in valleys without gardeners to care for them.

These wild bearded irises are of interest to some iris growers, for a variety of reasons. Some of us are just attracted to wild flowers, and like to see the plants as nature made them. Others are students of iris history, and it is these bearded species that are ancestral to our modern hybrids; growing them is like tracing the roots of our family tree. Others are hybridizers, curious to explore the untapped potential of these species.

Here is just a smattering of bearded iris species that may be of interest, with an emphasis on those that have been mentioned frequently in books and articles or that have featured prominently in the development of our modern bearded iris hybrids.

Iris pallida,
a form with variegated foliage

Iris pallida is a European tall bearded (TB) species, with light blue-violet flowers and straight stems with branching clustered near the top. To my eye, it is the most stately of all the bearded iris species.

I. variegata, another European species, is smaller, similar to  miniature tall bearded (MTB) irises in size, with zig-zag stems and distinctively colored flowers with yellow standards and falls marked in wine-red or brick-red.

These two species are probably the sole ancestors of the diploid tall bearded irises grown in gardens in the 1800s and early 1900s. They hybridize in nature, and these natural hybrids (amoenas, bitones, and blends) were collected by flower lovers and grown in European gardens. Any modern TB iris that has yellow (or pink or orange) coloration owes its color to I. variegata.

Iris variegata

The other wild irises important in the development of the modern TBs were a range of different tetraploid plants from various locations in the eastern Mediterranean. These include I. cypriana, I. trojana, I. mesopotamica, and some named clones such as 'Amas' and 'Ricardi'. All are purple bitones and large, well-branched plants. The botanical status of these is not as clear as might be, but every modern TB descends from them in some fashion. It was hybridizers of the early 20th century who crossed the colorful diploid pallida/variegata hybrids with these large tetraploids to create the modern tetraploid TBs that have become the most popular and widely grown of all irises.

Iris aphylla

Moving down in height, we come next to I. aphylla, a species from eastern Europe that is usually similar to standard dwarf bearded (SDB) or intermediate bearded (IB) irises in height, but copiously branched, the lowest branch usually emerging right at ground level! The flowers are dark violet, and beards usually bluish. It has been used in two different ways in breeding modern bearded irises: first in breeding "black" TBs, and then later in the work of Ben Hager and others creating the tetraploid MTBs. See my earlier blog post Our Debt to Iris aphylla.

In the realm of dwarf species, the earliest known to western European gardeners was I. lutescens (once called I. chamaeiris), which is native to the warm Mediterranean areas of Spain, France, and Italy. It was the basis for our garden dwarf bearded irises until the 1950s. Its height varies, spanning the modern MDB and SDB classes and sometimes growing even a bit taller. Colors are yellows, violets, whites, and blended and bitoned versions of those colors. See my post Iris lutescens: The Dwarfs that Time Forgot.

Iris pumila seedlings

The most important dwarf species in the development of modern dwarf and median irises is the species I. pumila, native to cooler, higher regions of eastern Europe. It is quite tiny, usually only about 4 inches tall, with blooms that appear almost stemless and  spring straight from the rhizomes. It has an extensive color range, from white to blue, purple, rosy, and yellow, usually with a darker spot of violet, red, or brown. It came to the attention of iris breeders in western Europe and the US rather late, in the mid-20th century. Once "discovered," however, it became a power player in iris breeding. I. pumila, when crossed with TBs, produced the modern SDB class, and through them the modern MDBs and IBs as well. See Iris pumila: A Tiny Treasure.

Iris reichenbachii grows wild on the Balkan peninsula, where it exists in both diploid and tetraploid forms. The flowers are rather long in form, and most are either a dull yellow or a grayish violet. This species is notable in the history of iris breeding for introducing the "dominant amoena" gene into the TB gene pool through the work of Paul Cook. Most modern bicolors have I. reichenbachii back somewhere in their family tree. See The Untapped Potential of Iris reichenbachii.

Iris reichenbachii

Also worthy of note is I. reichenachii's diploid relation, I. suaveolens (once called I. mellita). It is smaller than I. reichenbachii, but otherwise similar. It is noted for its sickle-shaped leaves, in some forms edged in a narrow line of red-violet pigment.

I hope this line-up of bearded species has piqued your interest. They are nice additions to the garden for anyone who is curious about where our garden iris "came from" or is attracted to the simple beauty of wildflower irises. One sometimes finds a few bearded species available from commercial iris growers, but more are consistently available through various seed exchanges from societies like the Species Iris Group of North America, the Scottish Rock Garden Club, the British Iris Society, or the Dwarf Iris Society.

Why not "go wild" and try some bearded species this year!

Miniature Dwarf Bearded Irises: A Starter Kit

By Tom Waters

This time of year, most gardeners in the northern hemisphere are patiently (or not) waiting for spring to come. If you are a bearded iris enthusiast like me, that probably means you are anticipating the earliest blooming of them all: the delightful miniature dwarfs. 

In the American Iris Society classification system, miniature dwarf bearded (MDB) include bearded irises up to 8 inches (20 cm) in height. Often overshadowed by their larger relations, the standard dwarf bearded (SDB), the MDBs nevertheless offer something special to the iris garden. Many of them bloom before the SDBs, when there is little else in flower. Their daintiness gives them an added charm: some iris enthusiasts are fascinated by tiny flowers and enjoy the surprise of encountering an unexpected bloom in some little corner of the garden. If you try growing an MDB, you'll be glad you did!

But how to get started? Many commercial growers only offer the larger bearded irises, and those that do sell MDBs may have just a few. With SDBs so outnumbering the MDBs, it can take a little extra effort and attention to seek out these tiny gems. In this post, I make a suggestion of a "baker's dozen" MDBs for someone looking to get started. This is not just a list of personal favorites; the irises in the list have been chosen because they represent the full range of the class, in terms of color, form, climate adaptability, genetic type, and historical era. This is important because not all MDBs are alike. Only by sampling a full range of types can you get a good feeling for what the class has to offer and discover your own preferences. All the irises on the list have been available commercially in recent years and are widely grown in gardens where MDBs are found. They should not be too difficult to obtain. 

In addition to the obligatory hybridizer and year, I have also included the ancestry type of each iris in the list. Type I MDBs come from SDB breeding, type II from crosses between SDBs and the species Iris pumila, and type III are pure I. pumila. For a basic introduction to these types, see my earlier blog post Dwarfs for Every Garden. For a more thorough, technical explanation, see my article The Miniature Dwarfs, which first appeared in the 2019 edition of the Dwarf Iris Society Portfolio.

‘Alpine Lake’ photographed by Tom Waters

'Alpine Lake' (A. and D. Willott 1981, type II) is a much-loved classic MDB with crystal white standards and falls with a pastel blue spot. Virus sometimes makes the falls a bit splotchy, depending on weather; but it is still one of the best.

‘Beetlejuice’ photographed by Tom Waters

'Beetlejuice' (P. Black 2013, type I) is a unique plicata with distinctive "whisker" lines on the falls. It sometimes sends up stalks that push the height limit of the class, but the compact shape of the flowers preserves its "dwarf" look.

‘Cinnamon Apples’ photographed by El Hutchison

'Cinnamon Apples' (P. Black 1990, type I), one of Paul Black's earlier creations, is notable for its rich reddish brown color in a class where blue, purple, yellow, and white tend to predominate.

‘Ditto’ photographed by Barbara-Jean Jackson

'Ditto' (B. Hager 1982, type I) is not only a delightful little iris with its cream color and bluish red spot, but it also reblooms in some climates.

‘Dollop of Cream’ photographed by Tom Waters

'Dollop of Cream' (P. Black 2006, type I) is a personal favorite. Earlier than most type I MDBs, it often ushers in the season here. I also appreciate the pastel color and the tasteful ruffling that is not too overdone.

‘Gecko Echo’ photographed by Jeanette Graham

'Gecko Echo' (B. Kasperek 2007, type I) is unmistakable for its deep mustardy fall spot.

‘Gold Canary’ photographed by Tom Waters

'Gold Canary' (A. and D. Willott 1981, type II) really lights up the garden in early spring. 

‘Hobbit’ photographed by Tom Waters

'Hobbit' (L. Miller 2004, type III), a tiny (4.5 inches!) blue pumila from Lynda Miller, is one of the best of this type.

‘Icon’ photographed by Tom Waters

'Icon' (Keppel 2008, type I) is a real zinger with its intense orange color and contrasting spot. Also an early bloomer here.

‘Little Drummer Boy’ photographed by Tom Waters

'Little Drummer Boy' (A. and D. Willott 1997, type III), a striking pumila with deep navy blue spots is an enduring favorite.

‘Royal Wonder photographed by Tom Waters

'Royal Wonder' (C. Coleman 2013, type III) is a robust, floriferous purple pumila - incredible impact for such a little iris.

‘Small Token’ photographed by Tom Waters

'Small Token' (L. Miller 2014, type II) is a rich and subtle red color on a very diminutive plant. Unique!

‘Zipper’ photographed by Jeannette Graham

'Zipper' (D. Sindt 1979, type II) is a standout with its deep yellow petals and electric violet beards. A true classic.

If you haven't tried the miniature dwarfs, I hope this "starter kit" gives you a good taste of what the class has to offer. If you already grow some, maybe this list will inspire you to pick up a few more and diversify your collection. Mine usually start blooming the last week of March here in northern New Mexico. I'm counting the weeks!

Ben Hager’s Master Plan to Save the MDB Class

 by Tom Waters

Forty-some years ago, when I was a precocious iris-obsessed teenager, I convinced my mother that our vacation to California to visit my sister and her family should become a tour of iris hybridizers’ gardens. So it happened that I ended up in Ben Hager’s living room, with a huge bouquet of ‘Beverly Sills’ on the coffee table, talking irises while my mom and sister politely enjoyed the ambience and hospitality.

Hager presented a somewhat intimidating figure, with his bald head, precise beard, and dry wit. He was also something of an iconoclast. At an after-dinner speech at the 1980 American Iris Society convention in Tulsa, he basically dismantled the whole premise of the judges’ training program by asserting that judging irises was an utterly subjective undertaking; and we should give up our pretensions of authority and just let people like what they like, which is what we all do anyway.

As a hybridizer, Hager had few equals, in my estimation. He worked with all classes of irises, and won high awards wherever he turned his attention. He created the tetraploid miniature tall bearded (MTB) irises almost single-handedly, by sheer force of will, it seemed. Furthermore, he had a rare combination of creative, inspired vision coupled with solid knowledge, dogged persistence, and patience. I rank him along with Sir Michael Foster and Paul Cook as one of the true ground-breakers in the history of iris development.

Today, I want to talk about one of Hager’s grand projects, an effort to re-create the miniature dwarf bearded (MDB) class, a work that spanned four decades.

In the 1970s, new MDBs were created by hybridizers combining standard dwarf bearded (SDB) with the species Iris pumila in various combinations. There were basically three possibilities: pure pumila breeding, pure SDB breeding, and SDB x pumila crosses.

Hager rejected pure pumila breeding (although he did introduce one, ‘Ceremony’, in 1986) for two reasons. First, being just a single species, it lacked the genetic variety needed to get the innovative colors, patterns, and forms that hybridizers crave. Second, he found its growth habit (mats covered in bloom, like rock-garden plants) to interfere with the appreciation of the form of the individual iris bloom.

Hager also rejected the SDB x pumila route, although it was very popular with other MDB hybridizers of the time. The issue here was poor fertility. Seedlings from this type of cross show only limited fertility, and are almost impossible to cross amongst themselves, making line breeding an impossibility. Hager felt strongly that a class of iris can only be improved and developed if a fertile family can be established, so that breeding can continue for many generations without fertility barriers arising. He introduced no MDBs from this type of breeding.

That left pure SDB breeding as a recipe for creating MDBs. Hager recognized this as the path of greatest promise, but not without reservations. This is the type of breeding with the greatest variety of colors and patterns, and the most adaptable to mild-winter climates. MDB-sized seedlings do arise from SDB x SDB crosses, but they are the exception (most seedlings will be SDBs like their parents). Hager wanted a more focused program than just waiting for these happy accidents. He wanted a line of MDBs that would produce more MDBs, consistently.

He found his answer in his tetraploid MTB work. The tetraploid MTBs were derived from crossing tall bearded (TB) and border bearded (BB) with the species I. aphylla, a many branched iris genetically compatible with TBs, although much smaller. Crossing his tetraploid MTBs with I. pumila, he reasoned, would produce irises of the same chromosome type as the SDBs, but presumably consistently smaller. Furthermore, they would be completely fertile with MDBs from pure SDB breeding, part of the same fertile family. You may read one of Hager's articles on this plan on the DIS website.

'Libation'

'Gizmo'

'Prodigy'

  

Hager introduced the first MDB of this type, ‘Prodigy’, in 1973. Its pod parent is a seedling of TB ‘Evening Storm’ (Lafrenz, 1953) X I. aphylla ‘Thisbe’ (Dykes, 1923). The pollen parent is the I. pumila cultivar ‘Atomic Blue’ (Welch, 1961). It is thus ¼ TB, ¼ aphylla, and ½ pumila.

Next came ‘Libation’ in 1975. It is a child of ‘Prodigy’ crossed with a seedling of MTB ‘Scale Model’ (Hager, 1966) x I. pumila ‘Brownett’ (Roberts, 1957). Since ‘Scale Model’ is half TB and half aphylla, ‘Libation’ has the same ancestry breakdown as ‘Prodigy’: ¼ TB, ¼ aphylla, and ½ pumila. ‘Libation’ won the Caparne-Welch Award in 1979.

The third and final of these initial progenitors of Hager’s MDB line is ‘Gizmo’ (1977), with the same parentage as ‘Libation’.

Hager then set about crossing these (and similar seedlings) with SDBs and MDBs from pure SDB breeding. As such outcrossing progressed, the amount of aphylla ancestry decreased and the amount of TB ancestry increased. The goal was to retain the small size conferred by I. aphylla, but bring in the diverse colors and patterns of the SDBs. Hager now had a line of seedlings specifically designed to consistently yield fertile MDBs in each generation.

In all, this project produced 34 MDB introductions. Hager died in 1999, but Adamgrove garden continued to introduce his MDB seedlings through 2003. Hager also introduced 19 MDBs from pure SDB breeding, and the above-mentioned pumila ‘Ceremony’.

Here is a list of all 34, grouped by the amount of aphylla ancestry present in each.

25% I. aphylla

Prodigy (1973), Libation (1975) Caparne-Welch Award 1979, Gizmo (1977) Caparne-Welch Medal 1987

Between 12% and 24% I. aphylla

Grey Pearls (1979), Bluetween (1980), Macumba (1988)

Between 6% and 11% I. aphylla

Footlights (1980), Bitsy (1991), Cute Tot (1999)

Between 4% and 5% I. aphylla

Pipit (1993), Jiffy (1995), Self Evident (1997)

3% or less I. aphylla

Three Cherries (1971), although not part of this line, is listed here for completeness, since it has aphylla in its ancestry from the appearance of TB ‘Sable’ (Cook, 1938) in its pedigree.

Petty Cash (1980), Hot Foot (1982), Bugsy (1993) Caparne-Welch Medal 2000, Dainty Morsel (1994), Doozey (1994), Fey (1994), Fragment (1995), Hint (1995), Chaste (1997), Ivory Buttons (1997), Nestling (1997), Trifle (1997), Simple Enough (1998), Small Thing (R. 1998), Sweet Tooth (1999), Wee Me (1999), In Touch (R. 1999), Downsized (2001), Dulcet (2001), Pattycake Baker Man (2001), Behold Titania (2003), Fair Moon (2003), Gallant Youth (2003), Into the Woods (2003), Pirate's Apprentice (2003)

'Grey Pearls'
photo: El Hutchison

As far as I can determine, other hybridizers did not take up this project as Hager had envisioned it, although they did of course use a number of his irises in their own crosses. My own work with similar crosses has had mixed results. I cross tetraploid MTBs with pumila each year, but so far have only bloomed one cross to evaluate, MTB ‘Tic Tac Toe’ (Johnson, 2010) X I. pumila ‘Wild Whispers’ (Coleman, 2012). The seedlings were all too large for the MDB class, looking like elongated SDBs or MTBs with deficient bud count. So the MTB x pumila type of cross is by no means guaranteed to give MDBs in the first generation.

I do have an interesting MDB seedling from I. aphylla X I. pumila. This type of cross produced MDB ‘Velvet Toy’ (Dunbar, 1972). My seedling is 5-6 inches in height, and has a distinctive flowering habit. It is branched at the base like I. aphylla, with both branches bearing 2 terminal buds each. The four blooms open in succession, at the same height, with no crowding. It would be nice to see if this trait could be carried on to plants with a more refined flower. Crossing it with SDB ‘Eye of the Tiger’ (Black, 2008) gave seedlings that were SDB size or taller, though in a fun variety of color and pattern. I continue to make crosses with it, mostly selecting smaller MDBs to pair with it now.

So far, my work with I.reichenbachii X I. pumila seems the most promising in terms of giving me a consistent MDB line to work with.

Kevin Vaughn has reported good results using Hager’s ‘Self Evident’, and I have recently acquired this myself, as well as a few others from Hager’s line.

How should one assess this ambitious program? On some level, it can surely be deemed a success, as it gave Hager many successful and popular MDB introductions. Without detailed records from his seedling patch, however, it is hard to assess how consistent the line was or how much his selection work over the years contributed to the outcome. Perhaps similar results would have obtained just by applying the same selection effort to pure SDB lines.

'Self Evident'
photo: Jeanette Graham

We also have to note that Hager’s tetraploid MTB project is his most lasting legacy among the bearded irises classes. Tetraploid MTBs are here to stay, having been taken up by successive generations of hybridizers. The MDB project did not fare so well, although that may not be any fault of the plants themselves. Almost all new MDBs today are small selections from pure SDB breeding, not produced from MDB-specific lines as Hager envisioned. This may just be a numerical inevitability. There is so much work being done breeding SDBs that MDBs popping up in SDB seedling patches just can’t help but outnumber MDBs from the few dedicated lines that hybridizers have worked with. The situation is reminiscent of that of the BBs, where some good dedicated lines have been established, but they are still swamped by small selections from TB crosses, just because so many more TB crosses are made each year.

'Bugsy'
photo: El Hutchison

If you are interested in hybridizing MDBs, I encourage you to heed Hager’s wisdom and work toward MDB-specific breeding lines, perhaps using I. aphylla, perhaps carefully selected from SDB work, or perhaps using other species.

If you are not a hybridizer, but enjoy growing MDBs in your garden, please seek out and preserve the Hager MDBs discussed in this post. They are a window onto a fascinating thread of iris history.

 

 

The Classic MDBs

 by  Tom Waters

The world of dwarf and median irises was revolutionized in the 1950s when Paul Cook and Geddes Douglas crossed the dwarf species Iris pumila with tall bearded irises (TBs) to create what became known as standard dwarf bearded irises (SDBs). The new SDBs were not only lovely, varied, and useful garden plants in their own right; but they were fertile parents, leading to all sorts of new avenues for hybridizers.

Hybridizers soon tried crossing the SDBs back to both of the parent types, TBs and I. pumila. Crossing SDBs with TBs produced a whole new style of intermediate bearded irises (IBs), whereas crossing SDBs with I. pumila produced a new style of miniature dwarf bearded irises (MDBs).

'Bee Wings'
photo: El Hutchison

By ancestry, these new MDBs were 1/4 TB and 3/4 I. pumila. From I. pumila, they inherit daintiness, earliness of bloom, and floriferousness. The TB ancestry lends them a greater variety of color and pattern, and a bit more width and polish in flower form. Dwarf breeders and growers were delighted with these creations; and they became quickly popular, all but replacing the earlier dwarfs from I. lutescens breeding in just a decade or so.

'Alpine Lake'
photo: Tom Waters

The first MDB from SDB x I. pumila breeding to win the Caparne-Welch award was Alta Brown's 'Bee Wings' (Brown, 1959), which won the award in 1963.  By 1990, six others from this type of cross won the award. Especially notable among them were 'Zipper' (Sindt, 1978), a deep yellow with a stunning blue-violet beard, and 'Alpine Lake' (Willott, 1980), a soft near-white with a diffuse blue spot. I refer to these as "classic" MDBs, because they set the standard for the class during this time of great progress and interest.

'Zipper'
photo: Jeanette Graham

Another popular type of MDB was produced by crossing SDBs with each other and selecting irises that were small enough to fall under the height limit of the MDB class (currently 8 inches). These had the advantage of showing all the color patterns of TBs, including plicata and tangerine pink. Although both types were popular, hybridizers breeding specifically for MDBs preferred the SDB x I. pumila cross, which produced a much greater proportion of early-blooming, MDB-sized seedlings.

After 1990, the SDB x I. pumila cross gradually fell out of fashion, with most of the new MDBs coming from SDB x SDB breeding. The reason for this is two-fold. First, the SDBs had been steadily progressing in color, pattern, and form; and the classic MDBs from SDB x I. pumila could not really keep up. Second, fewer breeders were breeding specifically for MDBs and growing I. pumila for that purpose. Most breeders were instead working with their established SDB lines, which sometimes produce MDB-sized plants "by accident," as it were. So the SDB x SDB cross would do double duty, producing both SDBs and MDBs.

'Wee Dragons'
photo: Jeanette Graham

Classic MDBs are still being produced, however. My favorite recent one is Lynda Miller's 'Wee Dragons' (Miller, 2017). The recent Caparne-Welch winner 'Kayla's Song' (D. Spoon, 2008) is of complicated ancestry, but its overall appearance makes it likely that it too is 3/4 I. pumila and belongs in this category.

Although it is clear that the MDBs from SDB x SDB breeding will continue to dominate the class with their modern form and exciting color patterns, the classics should not be completely forgotten. The advantages of early bloom and guaranteed dainty size in all gardens should not be set aside too quickly. And since this type of cross is not often made these days, we don't have a very full picture of its potential when modern SDBs are involved.

'Kayla's Song'
photo: Ginny Spoon

Although my own hybridizing interests are focused elsewhere, I make some SDB x I. pumila crosses each year and donate the seeds to the Dwarf Iris Society seed sale, in the hopes of encouraging interest in the classic MDB cross.

If you grow MDBs, keep your eye out for classic MDBs that have I. pumila or one of its cultivars as a parent. They will delight you with their early bloom and daintier looks. 

Arilpums Are Here!

by Tom Waters

When I last wrote about my progress with hybridizing arilpums in September, I was eagerly anticipating this spring's bloom, with many new seedlings expected to bloom on established plants. I was not disappointed!

Aladdin's Gem

First, a little recap. Arilpums are hybrids between pure arils and the dwarf bearded species Iris pumila. When a tetraploid aril is used as the aril parent, theory predicts that the arilpum seedlings will be fully fertile amphidiploids. Historically, most arilbred dwarfs and medians have been produced by using arilbreds, diploid arils, and SDBs in various combinations, and the result has been infertile offspring, making it impossible to linebreed the smaller arilbreds to refine them and extend their potential. Arilpums are the way out of that difficulty. However, only a few have been registered and introduced: 'Barbarella' (Mathes, 1991), 'Aladdin's Gem' (Thoolen, 2002), and 'Topaz Talisman' (Jensen, 2015). Although producing fertile pollen, arilpums so far have shown little or no pod fertility, a disappointing setback.

Last spring, I had some luck with the two arilpum seedlings I bloomed, Q025-01, 'Merlin's Magic' X Armenian pumila seedling, and Q053-01, 'Tadzhiki Bandit' X 'Sudden Butterflies'. Both produced seeds for me, as did a seedling of George Hildenbrandt's, GH-11-4-2, 'Dunshanbe' X 'Hidden Dragon'. So it seemed there was hope after all for creating a line of fertile arilpums!

This spring reinforced my optimisim, and also gave a preview of the great variety of color, pattern, and form that is possible with arilpums.

Q068-14

Q068-04, with "monster beards"

Earliest to bloom were seedlings from cross Q068, 'Dunshanbe' X 'Wild Whispers'. I had over a dozen of these, most dark violet selfs with some aril look but without much distinctiveness. Two stood out, however. Q068-04 has massive caterpillar beards. Not exactly beautiful, but certainly memorable. Q068-09 is the best of the lot, with a clean oncocyclus shape and elegant look. 

Q068-09, the standout

The second cross to bloom was really exciting: Q066, 'Tadzhiki Bandit' X Caucasus pumila seedling. These were much smaller and more varied than the 'Dunshanbe' seedlings, showing many exciting colors and patterns. I've kept almost everything from this cross for further evaluation.

Q066-06

Q066-02

There was another from cross Q053, looking almost the same as its sibling that bloomed last year. I also had a few seedlings from cross Q070, 'Vera' X 'Royal Wonder', one of which was deemed worthy of a closer look.

Q070-01

I made a number of crosses with this year's arilpums, but was not very systematic or thorough about it. Seeds have not been harvested yet, so it is premature to say much about their pod fertility. But there are pods, even some bee pods, so I am optimistic. 

It's been about ten years work to get to this point, but at last I have a small cadre of arilpum seedlings to work with, and the future looks very promising.

Progress with Arilpums

by Tom Waters

When I wrote my previous blog post on arilpums early in 2019, I had to focus mostly on history and theory, as I did not yet have much to show from my own seedlings. That has now changed, and the current state of this project is even better than I had dared hope.

As explained in the previous post, arilpums are arilbreds dwarfs that come from crossing pure arils with the dwarf bearded species Iris pumila. If the aril parent is a tetraploid, theory says the resulting arilpums should be fertile amphidiploids, a sort of arilbred analog of the SDBs. They thus have the potential of ushering in a whole new "fertile family" of miniature arilbreds.

Waters Q025-01

This spring, I bloomed two arilpum seedlings, both prolific two-year-old clumps covered in bloom. The first, Q025-01, from 'Merlin's Magic' (a selection of Iris stolonifera) x P002-05, a pumila seedling of Armenian origin, has a dainty Regelia look and some nice veining. The second seedling, Q053-01, from 'Tadzhiki Bandit' x 'Sudden Butterflies' is larger and huskier, with flowers reminiscent of tall arilbreds with Regelia ancestry, such as 'Stars Over Chicago' or 'Saffron Charm'.

I also had good bloom this year on an arilpum seedling from

Waters Q053-01

George Hildenbrandt, GH-11-4-2, from 'Dunshanbe' x 'Hidden Dragon'. This is a charming dark arilpum with nice aril-like flower form.

Hildenbrandt GH-11-4-2

The remarkable thing is that all three of these seedling produced seed for me this year when crossed with other arilpums. In my previous post, I mentioned that earlier hybridizers working with arilpums had found them to be infertile as pod parents. That is clearly (and thankfully!) not a general rule! Here are my successful arilpum x arilpum crosses this year:

Q053-01 x Aladdin's Gem gave 38 seeds

Q025-01 x Q053-01 gave 9 seeds

GH-11-4-2 x Q053-01 gave 23 seeds

GH-11-4-2 x Aladdin's Gem gave 3 seeds

These are not huge seed yields, but they are certainly adequate for continued breeding. I am quite optimistic that a number of the second-generation seedlings from these crosses will be fully fertile, and it will be possible to line breed arilpums without having to constantly go back to the difficult aril x pumila initial cross. This will also open up arilpum breeding for hybridizers who live in areas where either arils or pumila are difficult to grow.

Next spring should offer even more excitement, as I have more than 30 arilpum seedlings from various crosses that will be blooming as two-year-old plants. I got a sneak preview of one this spring,  Q066-08, from 'Tadzhiki Bandit' x P018-02, a pumila seedling originating from the Caucasus mountains. It looks for all the world like a miniature rendition of its aril pod parent, giving a rather more "onco" impression than others mentioned in this post. It has not yet been tested for fertility.

Waters Q066-08

All this has been an exciting vindication of a breeding project motivated mostly by theoretic possibilities rather than concrete experience. I'm now confident that arilpums have a bright future ahead.

Hybridizing with Iris reichenbachii

by Tom Waters

Four years ago, I wrote a blog post here titled “The Untapped Potential of Iris reichenbachii”. At that time, I could comment on the use of I. reichenbachii in median breeding only as a promising theoretical possibility. Now, however, I have some solid results from my own hybridizing work to share.

As mentioned in the earlier post, I. reichenbachii exists in both diploid and tetraploid forms. The diploid forms can be used with diploid MTBs, while the tetraploid forms are compatible with TBs, BBs, and tetraploid MTBs. It was the tetraploid grouping that I was interested in, so my first priority was to acquire tetraploid forms of I. reichenbachii. Alas, none of the plants or seeds available commercially or through seed exchanges have been identified as either diploid or tetraploid, so I had to make this determination myself. Not being equipped to make chromosome counts, this meant making test crosses and patiently waiting for the results.

Happily, it turns out that the tetraploid forms are not uncommon. The first two reichenbachii forms I started crossing with both turned out to be tetraploid. One is a yellow form, a collection from Mt. Vikos in Greece. The second is actually a group of plants of unknown origin I raised from seed obtained from a collector in Czechia. Most of these are violet.

I. reichenbachii ex Mt. Vikos, Greece

Waters T009-02, purple tetraploid I. reichenbachii

Waters T051-01,
I. aphylla X I. reichenbachii ex Mt. Vikos

I have three fertile tetraploid seedlings now. The yellow Mt. Vikos form gave me seedlings with I. aphylla and with the tetraploid median plicata ‘Saucy’ (Craig, 1998, IB). One of the violet forms gave me a seedling with the tetraploid median ‘Night Mood’ (L. Markham, 2003, SPEC-X). All three of the seedlings fall in the SDB height range and have the slender stems of I. reichenbachii. None are any competition for the modern, ruffled, dramatically colored median hybrids being produced these days; rather, their value is in further breeding. Because these plants are so small and dainty, they can be used to add these qualities to tetraploid MTB or BB breeding programs. So the next step is to cross these seedlings with the best modern BBs and tetraploid MTBs. It would be nice to have all the color patterns, form, and substance the modern BBs have to offer, but in a line of plants that was consistently small and delicate. This project is already well underway, as I have hundreds of seeds from using these seedlings over the past two years.

Waters T059-02,
Saucy X I. reichenbachii ex Mt. Vikos

Waters T060-01,
Night Mood X T009-02

A second project using I. reichenbachii is directed toward producing dainty MDBs. Most modern MDBs are produced by accident - they are just seedlings from SDB crosses that fall below the 8-inch height limit. These MDBs can be very lovely in terms of flower form and color pattern, but they can easily grow out of class, and often lack the daintiness and early bloom that one hopes for in a true miniature dwarf.

SDBs are the result of crossing TBs with the dwarf species I. pumila. What if one used I. reichenbachii instead of TBs? The result should plants fully fertile with SDBs and modern MDBs, but much smaller. I have three seedlings so far (more on the way) from crossing the Mt. Vikos reichenbachii with the I. pumila cultivar ‘Royal Wonder’ (Coleman, 2013, MDB). One is purple, the other two are yellow. All our about 5 inches tall, with one or two terminal buds. They bloom earlier, overlapping the pumilas and the first MDBs. They are indeed fertile with SDBs and with MDBs from SDB breeding. Once again, the value of these seedlings is not in competing with the showiest modern hybrids, but in further breeding, where they can be expected to produce a line of consistently dainty and early-blooming MDBs. Again, this project is on its way forward, with many seeds from using these seedlings with modern MDBs and SDBs.

Waters S026-01,
I. reichenbachii ex Mt. Vikos X Royal Wonder

Waters S026-02,
I. reichenbachii ex Mt. Vikos X Royal Wonder

These projects using I. reichenbachii are not for the impatient; they are multi-generation endeavors. Yet, there is something uniquely satisfying in breaking new ground.