Iris hexagona

Iris hexagona has thick (around 2–2. cm in diameter), greenish, branching rhizomes, that can spread to form large colonies of plants.{{cite web |title=Iris hexagona |url=http://www.fs.fed.us/wildflowers/beauty/iris/louisiana/iris_hexagona.shtml |publisher=fs.fed.us |access-date=28 November 2014}} The rhizomes are shallow rooted and can spread up to {{convert|30|cm|in|abbr=off}} per plant.

Arising from the rhizomes are the basal leaves, which are yellow-green to bright green and sword-shaped.Stephen Elliott (1821) {{Google books|Bng5AAAAMAAJ|A sketch of the botany of South-Carolina and Georgia|page=46}} They can grow up to between {{cvt|30|–|100|cm|in|adj=mid|long}},Edwin B. Smith {{Google books|4HMxfXJYyzkC|Keys to the Flora of Arkansas|page=327}} (or 2 feet), and between {{cvt|1.2|–|3|cm|in}} wide. They overlap at the base, similar to a fan, but some leaves grow on the flowering stem. After the plant has flowered, the leaves wither and die, to re-grow in the autumn (for the next season).

The flowering stem (or stalk) grows up to between {{convert|30|–|90|cm|ft|abbr=on}}or 12–36 inches).{{cite web| title=Iris summary|date=14 April 2014 |url=http://www.pacificbulbsociety.org/pbswiki/files/Iris/Iris_Summary.pdf |publisher=pacificbulbsociety.org | access-date=28 November 2014}} The stem is usually straight but sometimes slightly zig-zag,{{cite journal |first=Daniel B. |last=Ward |title=KEYS TO THE FLORA OF FLORIDA – 28, IRIS (IRIDACEAE) | url=http://www.phytologia.org/uploads/2/3/4/2/23422706/932231-240wardirisesflorida.pdf |journal=Phytologia |date=August 2011 |issue=93 |volume=2 }} or flexuous (winding),John Darby (1841) {{Google books|FhklAQAAMAAJ|A manual of botany|page=241}} with 1 -2 branches.

At the top of the stem are several groups of flowers in later spring, between late March to May (in the US), and between June and July (in the UK). Each flower arises from an axil (or spathe), of a reduced leaf (except the top flower), and the single (or double) flowers open in succession. They have a slight fragrance which is similar to sandalwood.

The flowers come in a range of shades of blue, from violet, to bluish purple, to lavender. Although there are occasionally white or greenish-white forms.

The flowers are generally between {{convert|4|and|4.75|in|cm|abbr=off}} across. They have yellow signal, crest, ridge or mid-rib, and a perianth tube of 2–3 cm, and 3 sepals (or falls) that are widely spreading (about 2 inches or 5 cm) and arching downward. The 3 standards are smaller and narrower than the sepals.

It also has linear yellow anthers.

After flowering, the plant produces a seed capsule in early summer. The six-angled seed pod, (which gives rise to its name 'hexagona'), has a ventricose (a swelling on one side). It is between {{cvt|3|–|6|cm|in|adj=mid|long}}. The large and heavy pods, contain large light brown seeds that are D-shaped and {{cvt|4|-|6|mm}} across. The seeds are generally described as being 'corky', so they can float on the water.

As most irises are diploid, having two sets of chromosomes. This can be used to identify hybrids and classification of groupings.{{cite book | first= Claire | last=Austin | title= Irises: A Gardener's Encyclopedia | publisher= Timber Press, Incorporated | isbn = 978-0881927306 | year = 2005 | ol = OL8176432M }}

It has a chromosome count: 2n=44 (Riley, 1942).{{cite web |title=Iris hexagona Walter (Dixie Iris) |url=http://facstaff.hsc.unt.edu/rbarton/Iris/hexas/I_hexagona.html |publisher=facstaff.hsc.unt.edu |access-date=3 December 2014}} and 2n=44 (Snoad 1952).{{cite web |date=17 April 2014 |first=Brett |last=Barney |title=(SPEC) Iris hexagona Walter |url=http://wiki.irises.org/bin/view/Spec/SpecHexagona |publisher=wiki.irises.org (American Iris Society) |access-date=3 December 2014}}

It has the common name of Dixie iris,{{cite web |first=Kenneth L. |last=Hibbard |date=25 May 2010 |title=FDACS-P-00124 Volume 49, Number 3, May – June 2010 |url=http://www.freshfromflorida.com/Divisions-Offices/Plant-Industry/Plant-Industry-Publications/Tri-ology-FDACS-DPI/Volume-49-Number-3-May-June-2010/May-June-2010-Botany-Section |publisher=freshfromflorida.com |access-date=28 November 2014}}{{cite web |first=D. |last=Kramb |date=21 September 2004 |title=Iris hexagona |url= http://www.signa.org/index.pl?Iris-hexagona |publisher=signa.org |access-date=28 November 2014}}{{GRIN | accessdate=3 December 2014}} (Dixie is a common name for the southeastern United States.Daniel F. Austin {{Google books|7qgPCEiI4WMC|Florida Ethnobotany|page=603}}) and it also occasionally known as 'Carolina iris'.{{cite web |title=FNA Vol. 26 Page 374, 391, 392, 393, 394 |url=http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=242101704 |publisher=efloras.org |access-date=28 November 2014}}{{cite web |title=Common name: Carolina iris – Scientific name: IRIS HEXAGONA |url=http://luirig.altervista.org/naturaitaliana/viewpics2.php?rcn=31549 |publisher= luirig.altervista.org |access-date=3 December 2014}}{{Google books|xh-NE2dRdNsC|A Fifth Checklist of Tennessee Vascular Plants|page=73}}

In Florida, it was known as the 'Prairie iris', but this due to a population of Iris hexagona var. savannarum which was later classified as a synonym of Iris savannarum.{{cite web |title=Iris savannarum Small is an accepted name |date=23 March 2013 |url=http://www.theplantlist.org/tpl1.1/record/kew-322353 |publisher=theplantlist.org |access-date=26 November 2014}} Most of the I. hexagona population in Florida was re-identified as Iris savannarum.{{cite web |title=Irises of Florida Newsletter Spring 2003 |date=Spring 2003 |url=http://zydecoirises.com/Species/Florida/FloridaIrises.pdf |publisher=zydecoirises.com (Society of Louisiana Irises) |access-date=29 November 2014}}

The name 'hexagona' refers to the six angled seed head.

The Louisiana irises and the name of the series of Hexagonae are derived from Iris hexagona, which was published (in Latin) and described by Walter in 'Flora Caroliniana' page 66 in April–June 1788.{{cite book |title=Iridaceae Iris hexagona Walter |url=http://www.ipni.org/ipni/idPlantNameSearch.do?id=438698-1 |publisher=ipni.org (International Plant Names Index) |access-date=28 November 2014}}{{cite book |title=Flora caroliniana : secundum systema vegetabilium perillustris Linnaei digesta; characteres essentia |url=https://www.biodiversitylibrary.org/page/10001134#page/73/mode/1up |publisher= biodiversitylibrary.org |access-date=28 November 2014|year=1788 }}{{cite web |first=Tom W. |last=Dillard |title=FROM NEW ORLEANS TO NEW ZEALAND, History and Development of The Louisiana Irises |url=http://zydecoirises.com/Species/Species.htm |publisher=zydecoirises.com |access-date=28 November 2014}}

Iris hexagona is a name accepted by the RHS.{{cite web|title=Iris hexagona |url=http://apps.rhs.org.uk/horticulturaldatabase/hortdatabase.asp?ID=271759 |publisher=rhs.org.uk |access-date=4 December 2014}}

File:Iris hexagona (16828921605).jpg, US]]

Iris hexagona comes from the southeastern and south-central US states along the Atlantic and Gulf coasts, in Alabama, Florida, Georgia, Louisiana, Texas, Tennessee and South Carolina.

It is found in wetlands and low roadside ditches in Florida and South Carolina, and west of Tennessee River near Johnsonville in Benton County, Tennessee, Hollow Rock and Carroll County, Tennessee. It was found to be one of the rarest irises in Florida and South Carolina.

It was found in Nassau County and Duval County in north-eastern Florida in 1933. But these populations have been extirpated, although the populations in Dixie County and Taylor County are stable. Same as the population in the lowlands near the Santee River in South Carolina.

It is ordinarily found in swamps, ditches, or marshes and wet prairies.{{cite journal |last=Taylor |first=Sunni J. |last2= Willard |first2=Rees W. |first3=Joshua P. |last3=Shaw |first4=Mary C. |last4= Dobson |first5=Noland H. |last5=Martin |date=13 May 2011 |title=Differential response of the homoploid hybrid species Iris nelsonii (Iridaceae) and its progenitors to abiotic habitat conditions |journal=American Journal of Botany |publisher=Department of Biology, Texas State University–San Marcos |doi=10.3732/ajb.1100012 |volume=98 |issue=8 |pages=1309–1316 |pmid=21821591}}

The Louisiana irises generally all have similar cultivation requirements. They need 6 hours of full sunlight per day,), moist, acidic soils (pH of 6.5) with a high organic and fertility content.Neil G. Odenwald and James R. Turner {{Google books |S__s1QADDJoC|Identification, Selection, and Use of Southern Plants: For Landscape Design|page=316}} They have a high moisture requirement during the growing season to be able to flower prolifically.

The new leaves grow in the autumn and consequently suffer in winter (if heavily frosted).{{cite web| first=William | last=Dykes| title=Handbook of Garden Irises | year=2009| url=http://www.beardlessiris.org/reviews/handbook%20of%20garden%20irises%20-%20dykes.pdf | publisher=beardlessiris.org (The Group for Beardless Irises) | access-date=28 November 2014}}

They can be used planted by the edges of ponds and pools or they can be planted in the water – but need the rhizomes pinned into the ground to stop them floating away.

If grown in borders, they need a mulch to retain moisture (in the soil) and to protect the rhizomes from sun burn.

The iris seed is not hard to raise, but does take many years to germinate and then they take 3–5 years before reaching flowering stage.Nick Romanowski {{Google books|gQsVgaxl-9kC|Water Garden Plants & Animals: The Complete Guide for All Australia|pages=43–44}} The seed should be sown before they dry out.

Iris brevicaulis and Iris hexagona are primarily pollinated by bumblebees.{{cite journal |first1=Sunni J. |last1=Taylor |first2=Kendall J. |last2=AuBuchon |first3=Noland H. |last3=Martin |title=Identification of Floral Visitors of Iris nelsonii |url=http://www.eaglehill.us/SENAonline/articles/SENA-11-1/22-Taylor.shtml |journal=Notes of the Southeastern Naturalist |volume=11 |issue=1 |year=2012 |access-date=2 December 2014}}

Propagation is best carried out by division of the rhizomes, which is best carried out in late summer or autumn when the plants are dormant. The ground must be prepared before planting, with the addition of a generous amount of organic matter and the soils dug to about {{convert|6|in|cm}} deep (to allow for new root growth). Plants require dividing every 3–4 years to promote good flowering. They can combine with other plants but tend to 'move' to suitable positions. If using a fertilizer (or feed), sprinkle in late January or February, before the plant is in flower.

Iris giganticaerulea and Iris hexagona are considered too tender for cultivation in the UK,{{cite book |last=Stebbings |first=Geoff |year=1997|title=The Gardener's Guide to Growing Irises |url=https://archive.org/details/gardenersguideto00steb |url-access=registration |location=Newton Abbot |publisher=David and Charles |page=[https://archive.org/details/gardenersguideto00steb/page/18 18] |isbn=978-0715305393 }}{{cite book |last1=Cassidy |first1=George E.| last2=Linnegar | first2=Sidney | date=1987 |edition=Revised | title= Growing Irises |location=Bromley | publisher=Christopher Helm | isbn=978-0-88192-089-5}} although in Kew Gardens (in London) the plant is grown in a rock garden, near a stream.{{cite book |first1=Roger |last1=Phillips |first2=Martyn |last2=Rix |title=Perennials Vol. 1 |page=188 |year=1991 |publisher=Pan Books Ltd. |isbn=9780330327749}} Botanist William Rickatson Dykes recommends a sheltered position.

It is thought to be hardy to {{cvt|-15|C|F}} in the UK.

In the US, they best grown in the southeastern states.

It is listed as a native plant to be suitable use in landscaping in Georgia.Bonnie Harper-Lore and Maggie Wilson (editors) {{Google books|PsVpgfhWhRYC|Roadside Use of Native Plants|page=156}}

The rhizomes (thickened roots) of Iris hexagona contain poison. If eaten, it could cause nausea, vomiting, abdominal pain, diarrhoea and an elevated temperature. The roots, seeds and plant sap can also cause skin irritation if touched.{{cite web |title=Iris hexagona |url=http://plants.ces.ncsu.edu/plants/all/iris-hexagona/ |publisher= plants.ces.ncsu.edu |access-date=3 December 2014}}

Research has also been carried out on the effects of saltwater on the Iris. Normally, saltwater getting into a wetland ecosystem can destroy or damage many native plant populations. Iris hexagona is a salt-sensitive species. The 2-year research found that saltwater affected the iris flowering times by several days, since Iris flowers are only receptive to pollinators for 2 days or less. This could have significant effects on iris colonies. It also means that the iris can be 'stressed' during episodic events (such as tropical storms).{{cite journal |last=Van Zandt |first=Peter A. |last2=Mopper |first2=Susan |date=November 2002 |title=Delayed and carry-over effects of salinity on flowering in Iris hexagona (Iridaceae). |url=https://www.researchgate.net/publication/51212004 |journal=American Journal of Botany |publisher=Department of Biology, University of Louisiana at Lafayette |volume=89 |issue=11 |pages= 1847–1851|doi=10.3732/ajb.89.11.1847 |pmid=21665613 |access-date=7 November 2014|doi-access=free }}

{{Reflist}}

• Correll, D. S. & H. B. Correll. 1975. Aquatic and wetland plants of southwestern United States, 2 vol.
• Correll, D. S. & M. C. Johnston. 1970. Manual of the vascular plants of Texas.
• Duncan, W. H. & J. T. Kartesz. 1981. Vascular flora of Georgia: an annotated checklist.
• Godfrey, R. K. & J. W. Wooten. 1979–1981. Aquatic and wetland plants of southeastern United States, 2 vol.
• Mathew, B. 1981. The Iris. 107–108.
• Radford, A. E. et al. 1964. Manual of the vascular flora of the Carolinas.
• Thomas, R. D. & C. M. Allen. 1993–. Atlas of the vascular flora of Louisiana.
• Wunderlin, R. P. 1998. Guide to the vascular plants of Florida.
• Marie Caillet (Editor), 2000, The Louisiana Iris: Taming of a North American Wildflower.

• [http://w3.biosci.utexas.edu/prc/Monocots/MonocotHTML/data/pages/IRHE2-o.html Image of seed capsule of Iris hexagona]
• [https://www.flickr.com/photos/billbouton/14253816733/ Image of Iris hexagona flower] on Flickr

{{Commons category-inline|Iris hexagona}}

{{Wikispecies-inline|Iris hexagona}}

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hexagona

Category:Plants described in 1788

Category:Flora of the Southern United States