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!

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.

 

 

Our debt to Iris aphylla

Tom Waters

I. aphylla

The European bearded iris species Iris aphylla has contributed to the development of modern bearded irises in a number of different ways. It still remains of considerable interest to hybridizers, particularly those working with the median classes.

The species is native to much of eastern Europe, with a range extending farther north than other bearded species. This makes it thoroughly winter hardy. It goes completely dormant in winter, losing all its leaves right to the ground. (The Latin word aphylla means "leafless".) The flowers are violet, although some recessive white and other off-color forms exist. The flowers themselves are not particularly glamorous, being often narrow and of poor substance. One of its most distinctive characteristics is prolific basal branching, with long branches starting low on the stalk, not infrequently at the point the stalk emerges from the rhizome. It varies in height, with forms as small as 30 cm and as tall as 60 cm or more. Both wild-collected forms and garden cultivars of the species have been registered and circulated.

I. aphylla 'Slick' (Lynn Markham, 2003)

Happily, I. aphylla has a similar chromosome complement to that of our modern tetraploid tall bearded (TB) and border bearded (BB) irises. This means it can be crossed with them to produce fertile seedlings that can be continuously worked with and improved for as many generations as one likes.

Early breeders showed little interest in medians, and simply worked I. aphylla into TB lines. It was found to contribute two interesting traits: an intensification of violet flower color, and blue or violet beards! Many early approaches to black in TB irises, such as 'Sable' (Cook, 1938) and probably 'Black Forest' (Schreiner, 1948), derive from I. aphylla. It is also behind many whitish or light blue TBs with blue or violet beards. In these irises, the dominant white found in TBs interacts with the intensification of violet pigment from I. aphylla.

When enthusiasm for median irises blossomed in the 1950s, with the formation of the Median Iris Society and the establishment of the four classes of median irises, creative breeders began to consider the potential of I. aphylla to add variety to these classes.

'Tic Tac Toe' (Johnson, 2010)
tetraploid MTB descended from I. aphylla

The most ambitious of such undertakings was Ben Hager's project to create tetraploid miniature tall bearded (MTB) irises. This class had been created with diploids in mind. Most TB irises from the 1800s and early 1900s were diploid, with a daintiness that was lost when tetraploids came to dominate. Early MTB breeders had taken these daintier TBs and bred them for even smaller size and greater delicacy. The MTBs were promoted as subjects for flower arranging. Tetraploid TBs, however, showed more different colors (such as tangerine pink), wider form, and better substance. Could these traits from the modern TBs be transferred to irises dainty enough to qualify for the strict requirements of the MTB class? Hager set about proving that they could. He crossed I. aphylla with small TBs and BBs, and then kept breeding toward the MTB requirements. After many generations of work, he established a line of tetraploid MTBs. Although these did not look exactly like the diploid MTBs (I. aphylla yields straight, upright stalks with vertical branching, whereas diploid MTBs often have a more zig-zag branching style), they had an appeal all their own. The first pink MTBs were Hager's tetraploids from I. aphylla.

'Saucy' (Craig, 1998)
tetraploid IB descended from I. aphylla

Hager's work was carried on by Jim and Vicki Craig, who combined Hager's irises with their own crosses involving different forms of I. aphylla. They introduced not only tetraploid MTBs, but BBs and IBs from the same breeding lines. This enhanced the variety of all three classes. They even produced a couple that were small enough to qualify as standard dwarf bearded (SDB)!

Others have worked with I. aphylla over the years, and continue to do so. Some hybrids that a relatively close to the species itself have been registered in the SPEC-X category. Paul Black's "small-flowered TBs" owe a debt to I. aphylla.

This species has contributed a great deal to the variety we find in both TBs and medians today. Do you grow any irises with I. aphylla ancestry? I'd wager you do!

'Night Mood' (Lynn Markham, 2003)
SPEC-X from 'Blackbeard' X I. aphylla 'Dark Violet'