Two members of the iris family, one large, one small, Iris versicolor is a long-lived perennial with large purple flowers; Sisyrinchium montanum is short-lived, but readily self-seeds. Iris versicolor ranges from Maine west to Nebraska, south to Arkansas; Sisyrinchium montanum is common from Maine south to Virginia.
By Pamela Johnson
There are native plants, shrubs, and trees that occupy enough uncultivated ground to capture attention whenever their salient features announce themselves: a long swipe of native hawthorn (Crataegus spp.) that enlivens and colonizes a stretch of roadside; a bridge embankment improbably cascading with American trout-lilies (Erythronium americanum ssp. americanum) like a terrestrial fish ladder; or the deep green gloaming of hemlock (Tsuga canadensis) woods suddenly illuminated by its new, tender, chartreuse growth. The revelations are everywhere in all seasons, reminders to anticipate, perhaps to remember and monitor plant populations from year to year.
A meadow passed almost daily has small, but salutatory eddies of blue iris (Iris versicolor) among its treasures, which also include glimpses of bobolinks and an occasional American bittern standing sentinel and believing itself to be well hidden in the alder thickets. This year, the meadow is not floriferous, but an old adjacent horse corral is blue with bloom, as if patches of late-day sky had fallen to earth, abandoned at dusk. The proportion of flowers overwhelms the foliage—all blue-violet with only a few exclamatory spears of green.
Concomitantly, a search for previously seen sweeps of strict blue-eyed grass (Sisyrinchium montanum) has been disappointing. There are a few plants, but not the usual saturation like that described by Mrs. William Starr Dana in 1894:
. . . the blossoms of the blue-eyed grass . . . so large and abundant that they seem to float like a cloud of color on the tops of the long grasses.[i]
There isn’t anything necessarily sinister about these fluctuations in plant numbers, or slight shifts in distribution. Wildflower populations respond to many cues, suffer deficits, and enjoy bounteous seasons. Unnatural disturbances are patent; natural changes require lengthy observance. Blue flag iris and blue-eyed grass are members of the same family, the Iridaceae, but the two plants would not necessarily exhibit parallel behaviors or undergo the same changes.
In Maine the iris family contains a small parcel of representatives. Three species of the genus Iris are recognizably iris-like, simpler-looking forms of the old-fashioned garden irises. The other iris genus is Sisyrinchium with four species and two varieties, all these not immediately recognizable as iris flowers.
Sisyrinchium montanum is a taxonomic mouthful for the diminutive blue-eyed grass. Some may find the plant inconsequential, easily mistaken for a few blades of grass when not in bloom. Certainly it contrasts with the frilly-headed hybrid garden irises that flounce onto June’s horticultural stage and exit quickly, leaving unattractive foliage behind.
Strict blue-eyed grass is short (usually only four to eight inches tall) with a fan of rapier leaves rising from a small fist of shallow yellow roots. When the flowers begin to open in mid-May, blue-eyed grass is arresting. Profoundly blue to blue-violet, the flowers seem bigger than they actually are because their color has such depth. There may be several flattened flower stalks with multiple buds on a plant, but only a single flower opens on each stalk, and only in sunlight. This ought to be one of the first wildflowers taught to a child—small stature, compact beauty, ease of identification (at least at the genus level [ii]), and perhaps even evocative of a particular field where the plants grow in lively abundance.
Iris versicolor, blue iris, is also easy to spot and identify in Maine, though there are two similar species found only in eastern central counties. Iris versicolor is a natural hybrid of one of those species, Iris hookeri, and of another native iris, Iris virginica, found farther south. Blue iris in an interspecific hybrid, an allopolyploid, that reproduces “true to seed”; anyone interested in Iris versicolor’s chromosomes may refer to “Parental Origin and Genome Evolution in the Allopolyploid Iris versicolor” Annals of Botany, Oxford Journals, Volume 100, Issue 2 (June 25, 2007)—or not.
Blue iris (or blue flag) blooms exuberantly in early June, the flowers lasting sometimes throughout the month. There are usually several flower stalks per plant, with the buds and blossoms (opening one at a time) held just above the sword-like leaves.
Both blue iris and blue-eyed grass possess markings on their petals and sepals called nectar guides. These striations and veinings are dark blue to deep purple, colors irresistible to bees and wasps of the Hymenoptera family. Not surprisingly blue iris and blue-eyed grass are pollinated by bumblebees (Bombus spp.); by mason bees (Osmia spp.), sweat bees (Halictidae), and digger bees (Anthophorini spp.); and by syrphid flies (Syrphidae).
There is nothing subtle about the patterns of nectar guides. The flower petals and sepals provide a bee-sized landing strip and the markings are like runway signs guiding the insects precisely to deposit and retrieve pollen. Blue iris has its female parts facing away from its anthers (male organs) to prevent self-pollination. Blue-eyed grass embellishes its flower center with a bright yellow star—yellow is another bee-favorite—to further announce the treats within.
Flowers advertize by color, structure, odor (sometimes fragrant, sometimes fetid), all mechanisms to attract invertebrate, avian, and a few mammalian pollinators to accomplish sexual reproduction. As much as humans admire, and covet, the wonderful panoply of flowering plants, our perception of their beauty is irrelevant to the complexly evolved and essential arrangement between insects and flowers.
That said, irises have been part of human history for millennia. Egyptian tomb friezes depict the unmistakable militant foliage and helmut-like blooms of irises. Frescoes at Knossos that survived the destruction of the Minoans in 1450 BC, show irises, along with violets, lilies, and the earliest discovered representation of roses. An Assyrian, King Tiglath-Pileses I (1114-1026 BC), cultivated gardens that included irises. Pythagoras, the Greek philosopher, used the trimerous petals and falls of an iris to define mathematical perfection.
Many plant historians[iii] believe that some species of iris got their names through Alexander the Great’s march to the Indus River in the 4th century BC. Since many irises originate in Asia Minor, it is not surprising to see the flowers used as a motif in art and architecture, from ancient Mediterranean cultures all the way to the Mughals in 16th century India.
Celebrated and traded, what was found in the East made its way back along the Silk Road, eventually north into Europe. The 6th century Frankish King Clovis I adopted the iris as the symbol of his conversion to Christianity. It was Louis le Jeune, in the 12th century, who appropriated the iris as his particular royal emblem; the fleur-de-lis, now often translated as a lily, was actually the iris, the flower of Louis. The familiar tripartite symbol has a petal each for wisdom, faith and valour.
Irises and lilies were commingled in medieval herb gardens, (their names and identites were often muddled until Linnaeus clarified the genera in 1753). Apart from beauty and symbolism, irises provided their roots to the important medicament and preservative orrisroot powder. The rhizomes of many Old World iris species are large, fleshy storage units, nutritional caches against the harsh xeric challenges of their montane origins. It was a natural hybrid of two iris species from Turkey’s Taurus Mountains that eventually delivered Iris x germanica, the garden iris to Europe, and on to the New World. North America returned the favor, sending its native irises, genetically closer to Japanese and Siberian irises, to England in the 17th century. Given the similarity in form between blue iris and the popular nursery varieties of the Far Eastern species, it is surprising that Iris versicolor is not seen more often in gardens.
Not every garden accommodates every wild plant. Spring ephemerals that luxuriate in cool humus, and beneath the filtered light of a tree canopy not yet full of leaves, will suffer in the sunny exposure of a traditional border garden. Woodland plants, herbaceous or woody, usually do better with protection from summer’s scorching afternoon sunlight. Ericaceous plants that like lean soils are at odds with the demands of common border gluttons like hollyhocks, clematis or hybrid roses. And there are always the incompatibilities of color, size, and form. Some native wildflowers look best when allowed to roam freely among their natural cohorts where they can also be planted in sufficient numbers that will benefit insects and other wildlife.
There are no constraints with either Iris versicolor or Sisyrinchium montanum. Both fit handsomely in formal or informal gardens and landscapes.
Iris versicolor is usually described as a wetland species, and while it thrives in damp meadows, it is tolerant of drier situations. It also blooms in full sun as well as partial shade. In bright sun, Siberian and Japanese irises require richer, moister situations than blue iris; and the non-native species require more frequent division to maintain blooms.
In spite of hosting various insects[iv] on its leaves, Iris versicolor’s foliage is appealing year-round, turning yellow-orange in autumn. Its seed capsules also provide interest to the garden’s winter mien. A low spot of ordinary soil could be transformed with a planting that weaves Iris versicolor, sensitive fern (Onoclea sensibilis), and common soft rush (Juncus effuses).
Sisyrinchium montanum is also suited to different garden situations, even dry ones if its roots are not disturbed. These small plants are happiest where they can roam by seeding themselves. Blue-eyed grass is delightful mixed with three-toothed cinquefoil (Sibbaldiopsis tridentata) as edging plants. The latter is an underutilized groundcover with shiny leaves, orange, red and deep green in autumn; its stalked white flowers coincide with those of blue-eyed grass. Low-growing pussy-toes (Antennaria spp.) and silverweed (Argentina anserina) have gray and silvery-green foliage, respectively; their leaves would accent the bluish green of blue-eyed grass’s leaves. It is always prudent to think of the virtues of foliage, along with the evanescence of flowers. Blue-eyed grass’s seed capsules are small green beads that darken as the seeds ripen—another sweet feature of this plant.
The seeds of iris and blue-eyed grass can be stored dry in a paper bag after collection, then sown out of doors in the fall or early winter. Germination occurs in mid-spring, and most plants will bloom during their second summer.
[i] Dana, Mrs. William Starr. 1895. How to Know the Wild Flowers. New York; Charles Scribner’s Sons. p.302.
[ii] Arthur Haines in Flora Novae Angliae is not the only botanist to counsel against glib identifications of the different species of blue-eyed grasses. There is much to appreciate, however, even with a rough idea of which species is which.
[iii] The Greek language provided the genus names of Iris and Sisyrinchium; a logical choice for Iris, from goddess of the rainbow, and a nod to the many flower colors of Mediterranean species; Sisyrinchium is problematic, translated as pig’s snout, goat’s skin, or woolen tunic- no one seems to find these appropriate.
[iv] One of these is the wasp mimic the Virginia Ctenucha (Ctenucha virginica), a day-flying moth; another inquiline is the Clubiona spider who folds iris leaves, lays her eggs, dies, and leaves her body behind to feed her offspring.