Species Iris Group of North America

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Iris tectorum

Botanical Name: Iris tectorum (added by D. Kramb, 26-OCT-03)

Botanical Synonyms:



Subgenus Limniris, Section Lophiris (Edmundas Kondratas, 17-NOV-03 )

Common Names:

Japanese Roof Iris (D. Kramb, 17-NOV-03 )

Chromosome Count:

2n=28 (D. Kramb, 03-OCT-04)

General Description:

Iris with fat rhizome, fans of broad ribbed leaves 2,5-5cm wide. Flower stems areslightly branched about 25-35cm tall with two or three flowers from each set of spathes. Flowers are about 8-10cm in diameter, lilac with darker veins and bloches. Very dissected crest on the falls. (Edmundas Kondratas, 17-NOV-03 )

Grows 10" to 14" tall with lilac flowers mottled darker, or white flowers, all with a lacy white crest. (D. Kramb, 03-OCT-04)

I grew I tectorum "Burma form" fromBIS seed, in the shade it flowerd at least 20" tall with much bigger, darker flowers. I have grown smaller forms well in limestone gravel among aril breds and junos in full sun. (Peter Taggart UK, 05-JAN-10)

Distinguishing Features:

White form "Alba" is known. In Japan was grown on top of roofs. (Edmundas Kondratas, 17-NOV-03 )

Preferred Habitat:

Wet sunny or half shaded places in humus rich soil with peat admixture. (Edmundas Kondratas, 17-NOV-03 )

Moist (not wet) soil and full sun to part shade. (Harangad Singh, 16-MAR-09)


Hardy to at least USDA Zone 6 (D. Kramb, 17-NOV-03 )

Upto zone 11 (Harangad Singh, 16-MAR-09)

Native Range:

South-western China, Burma (Edmundas Kondratas, 17-NOV-03 )

Central and southwestern China, Myanmar (formerly known as Burma), and Korea (D. Kramb, 03-OCT-04)

It has naturalised near human habitation in many parts of the Himalayas in India. (Harangad Singh, 16-MAR-09)

Status in the Wild:

Abundant (Harangad Singh, 16-MAR-09)

Commercial Availability:


Sources Cited:

B.Mathew "The Iris" (Edmundas Kondratas, 17-NOV-03 )

Info entered on 03-OCT-04 comes from the SIGNA Checklist of Iris Species. (D. Kramb, 03-OCT-04)

Additional Comments:

It multiplies rapidly and flowers without any difficulty..in warm zones such as 10 and 11 the rate mutliplication can be so high that thinning the offsets may be necessary to ensure flowering in the following season. (Harangad Singh, 16-MAR-09)

Where to buy it:

Sorry, but no sources of Iris tectorum have been uploaded yet.

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