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Iris versicolor

Blue Flag · Harlequin Blueflag · Purple Iris

Family IridaceaeGenus Iris

A deep violet iris beaded with dew, each hanging petal marked white and gold at its base
FlowerW. BulachCC BY-SA 4.0

About the plant

What it is and where it grows — not part of any germination protocol.

The plant

Habit
Bulb, Perennial, WildflowerExtension Gardener Plant Toolbox
Habit
rhizomatous geophytePlants of the World Online
Height
2-3 ft60-90 cmExtension Gardener Plant Toolbox
Spread
2-2.5 ft60-75 cmExtension Gardener Plant Toolbox
Flower
Blue, Purple/LavenderExtension Gardener Plant Toolbox
Native range
Canada, lower 48 states, St. Pierre and MiquelonPLANTS Database
Hardiness zones
3-9Extension Gardener Plant Toolbox

Growing conditions

Sun
Full sun; Partial ShadeExtension Gardener Plant Toolbox
Moisture
Frequent Standing Water, Moist, Occasional Flooding, Occasionally WetExtension Gardener Plant Toolbox

Toxicity is noted only where a source states it. No note here is not a finding of safety.

Sources: Extension Gardener Plant Toolbox — NC State Extension; Plants of the World Online — Royal Botanic Gardens, Kew; PLANTS Database — USDA NRCS.

Worth knowing

Two sources report 9 treatments between them. All are shown.

Protocol 1

DerivedN. C. Deno, 1996

Difficulty High Rated by us, not by the source.

Start around September 24, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on September 23, 2025.

  1. Dry storage

    Duration: 365 daysTemperature: 70°F 21°C

  2. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C Light: light

    17 germinated in this phase.

  3. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  4. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C Light: light

about 1.5 years from start to step 4. Germination happens during step 4, in 14 days.

58% germination in 14 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Iris p. 50Public domain
Show the original text
Iris (Iridaceae). The Aril Iris including Juno have been one of the most difficult groups to germinate. Section VI is devoted to this problem. Alternating cycles means alternating between 3 m at 40 and 3 m at 70 (just a reminder). I. versicolor germ. 70L(55% in 3-11 w). A second sample germ. 70L(32% in 4-9 w)-40-70L(36% in 1-4 w), 40-70L(42% in 2-5 w), 70D-40-70L(30%), and none in all other treatments. Seeds of this 2nd sample DS 1 y germ. 70L(17% in 9th w)-40- 70L(58% in 2nd w) and 70D(none).
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Iris p. 50. Quoted exactly. Every value on this card comes from this record, except the difficulty rating, which is ours; the step names come from a fixed list.

Protocol 2

DerivedN. C. Deno, 1996

Difficulty Moderate Rated by us, not by the source.

Start around January 18, 2027 for a May 3 last frost.

  1. Sow and cover

    Temperature: 70°F 21°C Light: light

No stated waiting before sowing. Then 77 days to germinate.

55% germination in 21–77 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Iris p. 50Public domain
Show the original text
Iris (Iridaceae). The Aril Iris including Juno have been one of the most difficult groups to germinate. Section VI is devoted to this problem. Alternating cycles means alternating between 3 m at 40 and 3 m at 70 (just a reminder). I. versicolor germ. 70L(55% in 3-11 w). A second sample germ. 70L(32% in 4-9 w)-40-70L(36% in 1-4 w), 40-70L(42% in 2-5 w), 70D-40-70L(30%), and none in all other treatments. Seeds of this 2nd sample DS 1 y germ. 70L(17% in 9th w)-40- 70L(58% in 2nd w) and 70D(none).
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Iris p. 50. Quoted exactly. Every value on this card comes from this record, except the difficulty rating, which is ours; the step names come from a fixed list.

Protocol 3

DerivedN. C. Deno, 1996

Difficulty Moderate Rated by us, not by the source.

Start around December 1, 2026 for a May 3 last frost.

  1. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  2. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C Light: light

about 3 months from start to step 2. Germination happens during step 2, in 35 days.

42% germination in 14–35 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Iris p. 50Public domain
Show the original text
Iris (Iridaceae). The Aril Iris including Juno have been one of the most difficult groups to germinate. Section VI is devoted to this problem. Alternating cycles means alternating between 3 m at 40 and 3 m at 70 (just a reminder). I. versicolor germ. 70L(55% in 3-11 w). A second sample germ. 70L(32% in 4-9 w)-40-70L(36% in 1-4 w), 40-70L(42% in 2-5 w), 70D-40-70L(30%), and none in all other treatments. Seeds of this 2nd sample DS 1 y germ. 70L(17% in 9th w)-40- 70L(58% in 2nd w) and 70D(none).
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Iris p. 50. Quoted exactly. Every value on this card comes from this record, except the difficulty rating, which is ours; the step names come from a fixed list.

Protocol 4

DerivedN. C. Deno, 1996

Difficulty High Rated by us, not by the source.

Start around September 10, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on September 9, 2026.

  1. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C Light: light

    32 germinated in this phase.

  2. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  3. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C Light: light

about 6 months from start to step 3. Germination happens during step 3, in 28 days.

36% germination in 7–28 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Iris p. 50Public domain
Show the original text
Iris (Iridaceae). The Aril Iris including Juno have been one of the most difficult groups to germinate. Section VI is devoted to this problem. Alternating cycles means alternating between 3 m at 40 and 3 m at 70 (just a reminder). I. versicolor germ. 70L(55% in 3-11 w). A second sample germ. 70L(32% in 4-9 w)-40-70L(36% in 1-4 w), 40-70L(42% in 2-5 w), 70D-40-70L(30%), and none in all other treatments. Seeds of this 2nd sample DS 1 y germ. 70L(17% in 9th w)-40- 70L(58% in 2nd w) and 70D(none).
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Iris p. 50. Quoted exactly. Every value on this card comes from this record, except the difficulty rating, which is ours; the step names come from a fixed list.

Protocol 5

DerivedN. C. Deno, 1996

Difficulty High Rated by us, not by the source.

Start around September 17, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on September 16, 2026.

  1. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C Light: dark

  2. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  3. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C Light: light

about 6 months from start to step 3. Germination happens during step 3; time not stated, 21 days assumed.

30% germination.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Iris p. 50Public domain
Show the original text
Iris (Iridaceae). The Aril Iris including Juno have been one of the most difficult groups to germinate. Section VI is devoted to this problem. Alternating cycles means alternating between 3 m at 40 and 3 m at 70 (just a reminder). I. versicolor germ. 70L(55% in 3-11 w). A second sample germ. 70L(32% in 4-9 w)-40-70L(36% in 1-4 w), 40-70L(42% in 2-5 w), 70D-40-70L(30%), and none in all other treatments. Seeds of this 2nd sample DS 1 y germ. 70L(17% in 9th w)-40- 70L(58% in 2nd w) and 70D(none).
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Iris p. 50. Quoted exactly. Every value on this card comes from this record, except the difficulty rating, which is ours; the step names come from a fixed list.

Protocol 6

DerivedN. C. Deno, 1993

Difficulty Moderate Rated by us, not by the source.

Start around January 18, 2027 for a May 3 last frost.

  1. Sow and cover

    Temperature: 70°F 21°C Light: light

No stated waiting before sowing. Then 77 days to germinate.

50% germination in 21–77 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Iris p. 156Public domain
Show the original text
Iris (Iridaceae). This genus gave -not only great diversity in germination behavior but also some of the most extended multicycle germination observed. Germination is always hypogeal, and true leaves develop in 'a week or two once the radicle emerges even when germination was delayed for years. Empty seed coats and deformed seeds are relatively easy to recognize so that seed counts and percent germination are accurate. A major problem is how to stimulate the germination of Oncocyclus and Regelia Iris since they have such extended natural germinations. Panayoti Kelaidis of the Denver Botanical Garden has iritorrmed me that Fritz Kummert In Austria, Frank Norris in Tennessee (USA), and David Shahak in Israel are growing Oncocyclus Iris from seed in large numbers. Panayoti said that there are reports that germination was much improved by rinsing the seed in dilute Chlorox (aqueous NaOCI) and rubbing off the seed coats after which the seeds germ. readily at 40. There are also reports that gibberelic acid and other chemicals stimulate germination. Data is needed using scientific procedures. A recent book, "The Iris" by B. Mathew, is devoted to this genus. Mathew divides the genus into six subgenera with further division into sections and series. His arrangement is used only in part. The species are arranged in alphabetical order for convenience with subgenus or section indicated in parentheses using the abbreviations B (bearded), Bx (beardless), E (Evansia), 'N (Nepalensis), .0 (Oncocyclus), P (Pardanthopsis), A (Regelia), At (Aeticulata), and X (Xiphium). I. versicolor (Bx) germ. 70L(50% in 3-11 w), 70D(none), 40-70L(40%), and 40- 70D(none). The sample in 70D was shifted to 70L after 8 w whereupon 55% germ. in the 2nd w. The photorequirement is typical of swamp Iris. Germination is much extended if the seed is kept in the dark as shown by 70-40-70(2/10)-40-70(1/10) and 40-70-40-70(5/20).
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Iris p. 156. Quoted exactly. Every value on this card comes from this record, except the difficulty rating, which is ours; the step names come from a fixed list.

Protocol 7

DerivedN. C. Deno, 1993

Difficulty Moderate Rated by us, not by the source.

Start around December 15, 2026 for a May 3 last frost.

  1. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  2. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C Light: light

about 3 months from start to step 2. Germination happens during step 2; time not stated, 21 days assumed.

40% germination.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Iris p. 156Public domain
Show the original text
Iris (Iridaceae). This genus gave -not only great diversity in germination behavior but also some of the most extended multicycle germination observed. Germination is always hypogeal, and true leaves develop in 'a week or two once the radicle emerges even when germination was delayed for years. Empty seed coats and deformed seeds are relatively easy to recognize so that seed counts and percent germination are accurate. A major problem is how to stimulate the germination of Oncocyclus and Regelia Iris since they have such extended natural germinations. Panayoti Kelaidis of the Denver Botanical Garden has iritorrmed me that Fritz Kummert In Austria, Frank Norris in Tennessee (USA), and David Shahak in Israel are growing Oncocyclus Iris from seed in large numbers. Panayoti said that there are reports that germination was much improved by rinsing the seed in dilute Chlorox (aqueous NaOCI) and rubbing off the seed coats after which the seeds germ. readily at 40. There are also reports that gibberelic acid and other chemicals stimulate germination. Data is needed using scientific procedures. A recent book, "The Iris" by B. Mathew, is devoted to this genus. Mathew divides the genus into six subgenera with further division into sections and series. His arrangement is used only in part. The species are arranged in alphabetical order for convenience with subgenus or section indicated in parentheses using the abbreviations B (bearded), Bx (beardless), E (Evansia), 'N (Nepalensis), .0 (Oncocyclus), P (Pardanthopsis), A (Regelia), At (Aeticulata), and X (Xiphium). I. versicolor (Bx) germ. 70L(50% in 3-11 w), 70D(none), 40-70L(40%), and 40- 70D(none). The sample in 70D was shifted to 70L after 8 w whereupon 55% germ. in the 2nd w. The photorequirement is typical of swamp Iris. Germination is much extended if the seed is kept in the dark as shown by 70-40-70(2/10)-40-70(1/10) and 40-70-40-70(5/20).
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Iris p. 156. Quoted exactly. Every value on this card comes from this record, except the difficulty rating, which is ours; the step names come from a fixed list.

Protocol 8

DerivedN. C. Deno, 1993

Difficulty High Rated by us, not by the source.

Start around June 19, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on June 18, 2026.

  1. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  2. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

  3. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  4. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

about 9 months from start to step 4. Germination happens during step 4; time not stated, 21 days assumed.

25% germination.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Iris p. 156Public domain
Show the original text
Iris (Iridaceae). This genus gave -not only great diversity in germination behavior but also some of the most extended multicycle germination observed. Germination is always hypogeal, and true leaves develop in 'a week or two once the radicle emerges even when germination was delayed for years. Empty seed coats and deformed seeds are relatively easy to recognize so that seed counts and percent germination are accurate. A major problem is how to stimulate the germination of Oncocyclus and Regelia Iris since they have such extended natural germinations. Panayoti Kelaidis of the Denver Botanical Garden has iritorrmed me that Fritz Kummert In Austria, Frank Norris in Tennessee (USA), and David Shahak in Israel are growing Oncocyclus Iris from seed in large numbers. Panayoti said that there are reports that germination was much improved by rinsing the seed in dilute Chlorox (aqueous NaOCI) and rubbing off the seed coats after which the seeds germ. readily at 40. There are also reports that gibberelic acid and other chemicals stimulate germination. Data is needed using scientific procedures. A recent book, "The Iris" by B. Mathew, is devoted to this genus. Mathew divides the genus into six subgenera with further division into sections and series. His arrangement is used only in part. The species are arranged in alphabetical order for convenience with subgenus or section indicated in parentheses using the abbreviations B (bearded), Bx (beardless), E (Evansia), 'N (Nepalensis), .0 (Oncocyclus), P (Pardanthopsis), A (Regelia), At (Aeticulata), and X (Xiphium). I. versicolor (Bx) germ. 70L(50% in 3-11 w), 70D(none), 40-70L(40%), and 40- 70D(none). The sample in 70D was shifted to 70L after 8 w whereupon 55% germ. in the 2nd w. The photorequirement is typical of swamp Iris. Germination is much extended if the seed is kept in the dark as shown by 70-40-70(2/10)-40-70(1/10) and 40-70-40-70(5/20).
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Iris p. 156. Quoted exactly. Every value on this card comes from this record, except the difficulty rating, which is ours; the step names come from a fixed list.

Protocol 9

DerivedN. C. Deno, 1993

Difficulty High Rated by us, not by the source.

Start around September 17, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on September 16, 2026.

  1. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

  2. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  3. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

  4. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  5. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

    1/10 germinated in this phase.

Steps after step 3 run on after germination.

about 6 months from start to step 3. Germination happens during step 3; time not stated, 21 days assumed.

20% germination.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Iris p. 156Public domain
Show the original text
Iris (Iridaceae). This genus gave -not only great diversity in germination behavior but also some of the most extended multicycle germination observed. Germination is always hypogeal, and true leaves develop in 'a week or two once the radicle emerges even when germination was delayed for years. Empty seed coats and deformed seeds are relatively easy to recognize so that seed counts and percent germination are accurate. A major problem is how to stimulate the germination of Oncocyclus and Regelia Iris since they have such extended natural germinations. Panayoti Kelaidis of the Denver Botanical Garden has iritorrmed me that Fritz Kummert In Austria, Frank Norris in Tennessee (USA), and David Shahak in Israel are growing Oncocyclus Iris from seed in large numbers. Panayoti said that there are reports that germination was much improved by rinsing the seed in dilute Chlorox (aqueous NaOCI) and rubbing off the seed coats after which the seeds germ. readily at 40. There are also reports that gibberelic acid and other chemicals stimulate germination. Data is needed using scientific procedures. A recent book, "The Iris" by B. Mathew, is devoted to this genus. Mathew divides the genus into six subgenera with further division into sections and series. His arrangement is used only in part. The species are arranged in alphabetical order for convenience with subgenus or section indicated in parentheses using the abbreviations B (bearded), Bx (beardless), E (Evansia), 'N (Nepalensis), .0 (Oncocyclus), P (Pardanthopsis), A (Regelia), At (Aeticulata), and X (Xiphium). I. versicolor (Bx) germ. 70L(50% in 3-11 w), 70D(none), 40-70L(40%), and 40- 70D(none). The sample in 70D was shifted to 70L after 8 w whereupon 55% germ. in the 2nd w. The photorequirement is typical of swamp Iris. Germination is much extended if the seed is kept in the dark as shown by 70-40-70(2/10)-40-70(1/10) and 40-70-40-70(5/20).
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Iris p. 156. Quoted exactly. Every value on this card comes from this record, except the difficulty rating, which is ours; the step names come from a fixed list.

How each step is done, in Deno’s words, and what Verified and Derived mean.

Germination trials

Readers’ own records of sowing this species, published after review. Share your trial · All trials

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