Iris BOTANY AND GEOGRAPHY

By Sylvain Ruaud

The iris, a universal plant? If we rely on the number of countries or regions associated with it, it seems that there are irises from all over the world. In the following lines we will make a kind of world tour of irises, referring to the names that have been given to them, whether in their botanical name or in their vernacular name.

Iris of England

The iris known as “English iris” is actually the species I. latifolia or X. latifolium. Native to the Pyrenees and the north of Spain, it can be found, for example, in abundance in the Gavarnie cirque and the Tourmalet pass, on the mountain slopes. In the inexhaustible source of information that is the Internet, one can read this comment: "This erroneous name comes from the fact that around the year 1600, the convent of Eichstätt in Germany received the first large ovoid bulbs from England, which made the monks believe that this iris grew spontaneously near Bristol. Thus, cultivated under the name Iris bulbosa angliana, this plant became the iris of England. Maurice Boussard, a French specialist in iridaceae, developed the same information and, botanically, he added: "(The English iris) belongs to the Xiphium group (bulbous iris) which does not hybridize with any other species. The flowers range from white to purple and dark blue, through various shades of purple." (1)

Iris of Spain

Is there any confusion between the so-called Spanish iris and the English iris? Both are Xiphiums, but Maurice Boussard makes the distinction: "We group together under (the name of Spanish Iris) a set of natural or man-selected varieties of Xiphium vulgare, a botanical species spontaneously spread in the Iberian Peninsula (Spain and Portugal), with flowers in a variety of colors. The name of this species corresponds well to its geographical location, which is not the case of the irises of England.  The species and its varieties are part of the irises cultivated for cut flowers. (1) About the color of the flowers, Richard Cayeux, in "The iris, a royal flower" specifies that these colors are "always marked by a yellow spot on the sepals."

Iris of the Netherlands

While we are at it, let's stay in the Xiphium group because the irises of Holland constitute "a series of horticultural irises obtained by hybridization between two botanical species of bulbous iris of the Xiphium group (...)"(1) The colors obtained, and that we can see in the bouquets of florists, but also in our gardens when the bulbs are planted there, are in the tones of blue with a yellow spot on the sepals. It has become a very common plant.

Iris of Germany

It is the very famous I. x germanica, that we all know and that, for centuries, illuminates our gardens at the end of winter, with its flowers generally of a dark purple, but that can, because of innumerable spontaneous crossings, take all kinds of tones, from blue to purple. There has been much discussion about whether it is a true species or simply naturalized varieties. "It is characterized by its more or less evergreen foliage in winter and its large, fragrant purple spring flowers whose three erect, dome-shaped petals are lighter in color than the three drooping sepals, adorned with a bright yellow beard." (1) Its half-buried horizontal rhizome elongates through the tip, which bears leaves and stem, and laterally forms new growth points. It can be said to be one of the starting points of all bearded iris hybrids.

Iris of Italy

Let's continue our tour of Europe. The Italian iris is not strictly speaking a species, nor even a variety, but a local version of Iris x germanica, in its white form better known as I. Florentina, as well as Iris pallida, cultivated in Italy and much sought after in perfumery for the rhizome, from which the essence of iris is extracted, after a long and laborious preparation which makes its price.

Iris of Dalmatia

It is about Iris pallida which everyone agrees to say that it is native of Dalmatia, the region located in current Croatia, all along the coast of the Adriatic Sea. In June, flowering stems rise to the top of the foliage and bear flowers similar to those of Iris x germanica but of a pale blue color, deliciously perfumed. The Dalmatian iris, like the Italian iris, has a fragrant rhizome and is therefore cultivated for perfumery.

Iris of Algeria

Let us cross the Mediterranean to the iris of Algeria (or Algiers, quite simply). It is what botanists call I. unguicularis. It is Richard Cayeux who speaks best about it: "This iris of Algiers presents the great interest of a perfumed and winter bloom (in fact, from mid-November to mid-March). The relatively short-lived flowers are renewed for almost four months"(2) The color varies from white (variety 'Winter's Treasure') to bright mauve. This plant is widely grown in temperate regions, and many cultivars have been selected for ornamental gardens.

Iris of Siberia

Everyone who is interested in irises knows the Siberian iris. The species I. sibirica with thin, woody rhizomes and narrow, long and flexible foliage, which grows preferably in a humid environment and gives lovely blue flowers, is mainly classified under this name. It is found in Central and Eastern Europe, as well as in the Caucasus. In France, it is a rare and protected plant, which one meets in Alsace like in the Jura and, perhaps, still sometimes in certain meadows which border the river Charente.

There are very numerous and gorgeous hybrids of it. These, nowadays, exist in almost all colors. Siberian irises are now a large family of garden flowers, particularly decorative.

Iris of Lebanon

The Near and Middle East is full of irises of all kinds. It is even known that the tetraploid ancestors of our great garden irises come from these regions. The iris of Lebanon or Iris sofarana is endemic to the mountains of Lebanon. It is a species in great danger because of the political and economic circumstances of its country, but also because of its beauty, which makes it the prey of unscrupulous collectors. It belongs to the group of I. susiana (Susa iris) together with(Damascus iris), a group with huge and darkly colored flowers, very spectacular, but difficult to cultivate outside its region of origin.

Iris of Palestine

Let's stay in the same region, to admire the iris of Palestine (I. palaestina), an exotic flower classified among the Junos, which some authors renounce to classify among the irises.  These unusual plants can be described as follows: they have thick, fleshy roots that are maintained during the dormant period and are easily damaged. The flowers, which are born in the axils of the leaves, are superb in their variety of colors; they differ from the traditional iris form by their tiny petals which are either hanging or held horizontally. The flowers, either grayish green, or rather yellow, bloom at the end of the winter and are pleasantly perfumed.

Now let's go to the Far East to meet...

Iris of Japan

In the series of LAEVIGATAE there is among others I. ensata, which is the learned name of the iris of Japan. These flowers have been cultivated since time immemorial in Japan, where they enjoy an exceptional popularity. Here is what Richard Cayeux (2) says about them: "It is enough to have admired one day their flowers which seem to float in the air and their multiple associations of colors to understand (it). After the great garden irises, they are certainly the most cultivated hybrids in the world.”

Iris of Formosa

This time we are in the presence of what has long been called the "crested irises", which are part of the JAPONICAE series. I. formosana, and its cousin I. japonica are plants which do not lose their leaves, narrow and long, of a medium green, which carry flowers of small size, relatively numerous, on spindly but solid stems, white marked with lilac feathers and decorated with yellow ridges. They are very original flowers, easy to cultivate and whose bloom, in June, lasts approximately four weeks. I. formosana is native to the north-east of Taiwan, where it lives near forests, on the slopes of hills and on the slopes of roads, from 500-1000 m of altitude, which makes it a rustic plant.

To finish this long journey, we will cross the Atlantic and reach America.

Iris of Louisiana

Louisiana irises are man-made plants. The basic crosses were made between species of the HEXAGONAE iris series, native to the mouth of the Mississippi and surrounding areas: I. brevicaulis, I. fulva and I. giganticaerulea, to which Iris hexagona should be added. Later, I. nelsonii came to bring to the hybrids colors hitherto unknown in the group, and especially red. They are bulky and greedy plants, and are among the most beautiful of the iris world. Also, the most recent varieties are frost resistant. 

Iris of California

They are hybrids of rather recent appearance. Let us say that they appeared in the 1930s. Not in the United States by the way, but in Great Britain. At the beginning they were botanical species which were used, then interspecific crossings intervened, with an aim of joining the qualities of various species, all native of the West coast, between the State of Washington and that of California. The current cocktail is composed of a dozen species, but there are four that have been mostly used: I. douglasiana, I. innominata, I. tenax and I. munzii. The result is a hybrid that quickly forms strong clumps, which prefer acidic, well-drained soils, covered at flowering with numerous, usually round flowers, about 8 cm in diameter, in a remarkable choice of colors and patterns. 

Iris of Canada

Quebec, in Canada, has claimed the paternity of I. versicolor to the point of having made it its national flower, as legally as possible, in 1999. Iris versicolor is the American cousin of I. pseudacorus, an iris that grows in Europe in ditches and is covered with yellow flowers. I. versicolor is very similar to it. Its flowers, rather large but narrow, have sepals which flare at the point, which makes all their charm. Of blue or purplish color, they are decorated with a white signal and are tinted yellow or gold in the heart. It is this blue color that makes them commonly called "blue flag" in the United States. It is part of the LAEVIGATAE series. Its Asian origins give it a strong resistance to cold. I. versicolor lives preferably in a humid, even flooded environment, but it can also grow in a drier soil provided that it is watered copiously. It nevertheless needs an acid soil, rich in nutrients.

Thus ends our tour of the globe.

Whether they are botanical or horticultural plants, all these irises demonstrate the great diversity of the genus and attest to its worldwide distribution.

(1) Maurice Boussard, "L'ABCdaire des iris".

(2) Richard Cayeux, "L'Iris, une fleur royale".

Location, Location, Location

By Bryce Williamson

Although I have been growing irises for over 55 years, I learn something new every iris season, or a lesson from the past is reinforced. In the last few years it is the term “location, location, location” and my discovery that it not only applies to real estate but also to gardening.

'Lavender Moonbeams'--Rick Tasco image

Two years ago, I decided to add three I. unguicularis, sometimes called the Algerian iris, to the garden, but my acquiring the plants coincided with my breaking six ribs and having to find a spot for the gardeners to plant them while I healed. The location was not ideal—my first lesson was that I should have found a location where I walk every day, not in a bed where I can go days without looking at the plants. The second thing I learned, and it is a recommendation for other gardeners who might like to grow these winter flowering irises, was find ‘Lavender Moonbeams’ because it flowered well.

Last year I made the decision to move the irises from the backyard into the front yard. No irises have grown there in seven or eight years and I expected them to do well in this new location. I had learned my lesson from the past and fertilized more heavily and add organic matter to the soil. That we did by moving 7 yards of potting soil mix into an area 600 square feet and a fifty pound bag of 15-15-15 was also spread over the area; however, I tend to over plant and as a result, I ran out of room and needed to plant my arilbreds in a different bed by the walk.

I had Reynaldo hand dig the bed with a bag of potting soil, but as the arilbreds grew and then bloomed, they bloomed poorly. My lesson was that they needed more fertilizer and one bag of potting soil for even that small area was not enough. I’ve also learned that my tendency to want to replant 4 rhizomes of a variety needs to be curbed—I may have to settle for 3 rhizomes! I will have to watch myself or the 1200 square foot area we are preparing in the backyard will not be enough.

I have always thought that where I bought plants and bulbs determined the quality of the product. A couple of years ago, I decided to add some reticulates to the garden and, for once, I got the location right—along the front of the sidewalk where I walk at least 6 times ago. I picked up a cheap bag of Iris reticulata ‘Harmony’ from Costco and went to the most expensive and best of Silicon Valley’s remaining nurseries—the dwindling number of plant nurseries here is another story—for other colors and into the ground they went. I’m on the second year and ‘Harmony’ has bloomed well, though I learned that I should have planted the bulbs more closely together, and it is thriving, but the more expensive plants have grown and only thrown up a couple of flowers. There does not seem to be a tight connection between price and quality of the bulbs.

Sometimes I get the location right by mistake. Every few years, I scrounge the nurseries for Dutch iris, buying a dozen of each variety that I can find. They do well the first years, but fail to naturalize for a variety of reason. The amazing exception is ‘Sky Wing’, a soft lavender-blue that loves it location and flowers every year. It is planted at the edge of the water line for the sprinkler and I thought that location would be a kiss of death, but it likes it there. A large rock anchors that corner of the rose bed and that may help with Sky Wing. (Note that there is a Siberian called Sky Wings too).

With more than fifty springs under my belt for growing irises, each year I learn something new.

The World of Irises is the official blog of The American Iris Society. Now in its 99^th year, The American Iris Society exists to promote all types of irises. If you wish to comment on a post, you can do so at the end of the page and the author or the editors will reply. If you wish to learn more about The American Iris Society, follow the link.

The Winter Flowering Iris, Part 2

By Bryce Willliamson

In putting together the blog The Winter Flowering I. unguicularis, Mr. Richard Tasco answered my questions and provided images. The following interview has been constructed from our correspondence. I. unguicularis do provide good winter flowering plants in Zone 7 and up, but cannot be grown outside in other zones.

BW: How did you get started hybridizing I. unguicularis?

RT: During the 1998 season I made my first cross with the Iris Unguicularis.  This was I. Ssp Cretensis X Marondera.  Marondera is an unregistered large flowered Unguicularis of unknown origin.  I found reference to this clone in South Africa.  This cross produced 3 seeds, two of which germinated and one went on to die.  The other turned out to be my first Unguicularis introduction “Dazzling Eyes” (Tasco 2004).

Dazzling Eyes (Tasco)--image by Rick Tasco

In succeeding years I started to use more clones which I acquired:  Mary Barnard, Walter Butt, Alba, Lazica and of course Marondera.  Marondera more than any of the others proved to be a wonderful parent.  It was largely responsible for my goal of getting large flowers with large rounded petals in this class.  Lazica and Walter Butt did not produce anything worthwhile.  I was more successful with Alba and Mary Barnard.   Wishmaster (Tasco 2007) was Marondera X Mary Barnard.  This is a large medium purple flower.

BW: What were and are your goals in hybridizing?

RT: Another goal was to use Alba to create a very pale lavender along the lines of Walter Butt, but much larger.  This was achieved with my Lavender Moonbeams (Tasco 2014) by using Alba X Marondera.  I called it Lavender Moonbeams.  I’m still using Alba trying to get a white flower with blue shadings.  White flowers do appear in my seedlings but only in the second generation.  Such as Alba X Marondera and then Alba by the progeny of the first cross.  The percent of white flowers in any cross is about 10 percent, but most white flowers, like Alba, aren’t strong growers.  I’m working to improve that.

Lavender Moonbeams (Tasco 2014)--image by Rick Tasco

Still another goal was for dark flowers.  Result was Winter Echoes (Tasco 2011), this was a cross of Marondera X Mary Barnard.   I’m still working for something darker.

Winter Echoes (Tasco 2011)--image by Rick Tasco

The progeny of these crosses do not produce that much diversity and it is difficult to select something different and better.  One year I grew 800 seedlings and only selected two to introduce.  Currently I have about 700 unguicularis seedlings. 

Tasco 04-UNG-03-10--image by Rick Tasco

BW: Do you have any tips for gardeners?

RT: Unguicularis are easy growing plants that can grow and bloom in either full sun or partial shade.  In full sun the foliage may yellow somewhat and become upright making it difficult to observe the flowers in bloom.  In partial shade the foliage remains greener and tends to reflex so the flowers can be easily be observed.

Image by Rick Tasco

BW: What are some of the unusual characteristics of I. unguicularis?

Unguicularis do not have stalks.  They flower on elongated perianth tubes.  Some varieties have longer tubes than others, but most are between 8 and 15 inches.

BW: Do you have any special cultural recommendations?

RT: In our Central California climate it is best to plant or transplant Unguicularis at the end of October or the beginning of November.  Although most literature say they can grow in poor soil, I amend my soil with a good soil amendment, half and half, such as Miracle-Gro or Sta-Green (very comparable and less expensive than Miracle-Gro but only available at Lowe’s).  This makes a big difference in good growth and more flowers.

Rick Tasco's I. unguircularis seedling bed, February 3, 2017--image by Rick Tasco

From late spring thru October the plant is dormant and the roots will die.  When digging for transplant there will be many wiry roots that are dead.  With the onset of cooler and wetter weather the plants will begin to grow new fat white roots similar to Pacific Coast Natives.  I cut off all the dead and wiry roots before I transplant being careful not to cut the new fat white ones.  They transplant easily even into pots.

Tasco 04-ung-02-11_2_2013 (1)--image by Rick Tasco

Editor’s Note: For plants, two sources are available. Superstition Iris Gardens offer three of the four Tasco varieties this year in 4 inch pots for sale and can be contacted at randrcv@sti.net or search for the Superstition Iris Gardens page on Facebook; Plant Delight Gardens in NC sells them too and they have an on-line catalogue at https://www.plantdelights.com.

My sincere thanks to Mr. Richard Tasco for providing information and images.

The Winter Flowering Iris Unguicularis

By Bryce Williamson

Gardeners are always looking for ways to extend bloom season and iris gardeners are no exception. In his recent blog, Hooker Nichols talk about using Louisiana irises to extend the iris season after the tall bearded irises bloom; for those of us that live in a mild climate, there is a little grown iris that can start to flower as early as October and bloom during the winter months—I. unguicularis, sometimes called the Algerian iris. The term Algerian iris is a bit confusing since clones of I. unguicularis are found in the Greek islands, Greece, Syria, Tunisia, and even Turkey.

Lavender Moonbeams (Tasco)--image by Rick Tasco

With plants that grow 12 to 15 inches in height, the flowers can bloom in the foliage. Producing fragrant flowers off and on through winter, the buds are frost resistant though the flowers are not. Unlike most types of irises, I. unguicularis produce flowers over weeks and even months during the winter; however, the plants are loved by snails and slugs, making it necessary to keep the plants free of debris and snails and slugs under good control or they will eat the flowers before you have the chance to enjoy them.

As a plant from dry Mediterranean areas, this iris survive in the summer with only occasional moisture and grows and blooms in poor soil. I. unguicularis is recommended from USDA Zone 7 and higher only. While not widely grown in the United States, the Royal Horticultural Society has named I. unguicularis as one of the top 200 plants in the last 200 years.

Curtis's Botanical Magazine, 1869

Writing in Curtis’s Botanical Magazine in 1869, J. D. H. May noted that information about this iris was “was first published, without a specific name, in 1789, by Poiret, in his Voyage en Barbarie, v. ii. p. 96, and afterwards, first as I. stylosa, by Desfontaines in 1798, and then as I. unguicularis by Poiret, in 1799.” Today I. stylosa is no longer used to describe this fragrant little gem in the winter garden.

There has been some interest in I. unguicularis in what is now known as Silicon Valley for many years; the late Edith Cleaves, of Los Gatos, California, created the varieties 'Edith Cleaves', 'Winter Gay', 'Winter Goldback', 'Winter Memories', 'Winter Mystery', 'Winter Snowflake', and 'Winter Treasure', but they no longer seem to be in commerce. More recently, the noted Central Valley hybridizer, Richard Tasco, best known for creating award winning tall bearded, median, and arilbred irises, has been working with I. unguicularis too. This last year, he raised 600 seedlings.

Image by Rick Tasco

To obtain plants, two sources are available: Superstition Iris Gardens are selling three of the four Tasco varieties this year in 4 inch pots and can be contacted at randrcv@sti.net or search for the Superstition Iris Gardens page on Facebook; Plant Delight Gardens in North Carolina sells them too and they have an on-line catalogue at https://www.plantdelights.com.

Lifting, Dividing, and Transplanting Pacifica Iris

Kathleen Sayce

The seasonal forecast for the Pacific Northwest was for a mild, warm, drier-than-normal fall. Hmm. Warm, yes; dry, no. So far we've had a series of storms blow through, each one dropping around two inches of rain. For dry gardens (those that do not get additional irrigation water), this means that Pacifica Iris began putting out new roots a few weeks ago. New white roots means that these plants can be dug up and transplanted. 

'Premonition of Spring' in flower between storms; the flowers aren't perfect due to the weather and slugs, but provide a cheerful corner in the garden during winter. 

Pacifica Iris are notoriously fussy about being moved, particularly in climates with prolonged dry summers. I've mentioned before that checking the roots to make sure that there are 1-4 inch long white (live) roots is important for success. 

New roots on Pacifica Iris fans show that this plant is in active growth and can be moved. 

Today I went out between showers (the thunder, lightning and hail type of showers) to redo a densely overgrown patch of PCI seedlings. Let's not go into why I did not do this two or three years ago. As gardeners know, life often gets in the way of garden plans and ideal timing for gardening activities. 

There are five different irises in this patch:  four seedlings, one of which has not yet flowered, and one named variety. 

What a little procrastination can give you:  a near-solid mass of irises to separate and divide. If I'd waited another year, it might have been near-impossible to divide out the different seedlings. Spuria iris on the lower right (its long leaves were broken down in the last storm), 'Premonition of Spring' on the left, next to the cyclamen, and in the middle, three massively overgrown PCI seedlings. 

One of the seedlings is not going back into the garden. It came to me as orange-flowered I. innominata seed; by the second year it was clear that this seedling is really a Spuria Iris. So it's going south to Los Angeles, to a much warmer climate where it might actually flower.

The clue that this clump is not a Pacifica Iris:  the leaves were three to four times as tall as the other irises around it!

Pacifica Iris clump in the middle, Spuria clumps on the right with their leaves already partially cut back. 

Three of the seedlings are from open pollinated seeds from Debby Cole's garden on Mercer Island, Washington; the pod parent is her vivid PCI hybrid 'Egocentric'. I'm still evaluating the lavender flowered seedlings; the yellow seedling is a nice sturdy plant, and I'm sending starts to other gardens.

One of the lavender-flowered PCIs from an 'Ecocentric' pod parent seed lot. 

Another seedling from the same seed lot; sturdy short plant, waiting to see the flowers for one more season before I decide to keep or toss. 

A yellow flowered Pacifica seedling, pod parent, I. 'Egocentric', from Debby Cole.  This one I will keep. The plant is sturdy, the flowers are held well above the foliage, and are well shaped. 

The fifth iris clump in this patch is 'Premonition of Spring', Garry Knipe's winter flowering selection.  I divided this one into two smaller masses and replanted one near the other. Like Iris unguicularis, it flowers sporadically from fall through early spring. In fact, both clumps (POS and I. unguicularis) have buds or flowers right now, and will flower occasionally during fall-winter-spring months. I plan to move an I. unguicularis clump nearby. 

Once each clump is out of the ground, I use clippers to cut apart the fans. Sturdy rhizomes grow between groups of fans, and my hand clippers easily cut through them. 

A nice pile of more than one dozen fans are going to other gardens. 

After replanting, the plants have room. Next spring I'll be able to see the flowers on each plant more easily, evaluate them, and decide which seedlings to keep. I also found two mesh bags with seeds inside––these are going to be scattered in a patch of native grasses to naturalize.

Lifted, divided, and replanted, and ready to grow on this fall and into next spring.

I was done just in time to avoid the next shower!