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About the plant What it is and where it grows — not part of any germination protocol.
The plant
Habit Herbaceous Perennial, Water Plant Extension Gardener Plant Toolbox
Habit rhizomatous geophyte or helophyte Plants of the World Online
Flower Gold/Yellow Extension Gardener Plant Toolbox
Blooms Spring, Summer Extension Gardener Plant Toolbox
Native range Albania, Algeria, Austria, Baleares, Baltic States, Belarus and elsewhere GBIF Backbone Taxonomy
Hardiness zones 5-9 Extension Gardener Plant Toolbox Growing conditions
Sun Full sun Extension Gardener Plant Toolbox
Soil pH Acid (<6.0), Neutral (6.0-8.0) Extension Gardener Plant Toolbox
Moisture Frequent Standing Water, Moist, Occasional Flooding, Occasionally Wet Extension 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; GBIF Backbone Taxonomy — Global Biodiversity Information Facility.
Worth knowing Pseudacorus means false acorus, for leaves like those of sweet flag, which is not closely related. An 18th-century French naturalist, Boissier de Sauvages, thought the fleur-de-lis may come from this iris rather than a lily. Wikipedia: Iris pseudacorus This source reports 7 treatments. All are shown.
Protocol 1 N. C. Deno, 1993 Difficulty Moderate Rated by us, not by the source.
Start around May 22, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on May 21, 2026.
1 Clean the flesh off the seed
2 Leach in running water
Duration: 28 days
Washed and cleaned daily for 4 weeks.
3 Dry storage
Duration: 180 days · Temperature: 70°F 21°C
4 Cold moist stratification
Duration: 90 days · Temperature: 40°F 4°C
5 Warm moist stratification
Duration: 90 days · Temperature: 70°F 21°C · Light: light
about 10 months from start to step 5. Germination happens during step 5; time not stated, 21 days assumed.
75% 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. pseudoacorus (Bx) germ. 70L(55% in 2-12 w)-40-70L(9%), 40-70L(3/4), and none in 70D or 40-70D using seeds which had been DS 6 m at 70 followed by WC for 4 w. Germination was lower without the WC as shown by 70L(1/6), 70D-40-70L(5/7), 40-70L(6/1 1), and none in dark treatments. Fresh seed germ. 40-70L(50%) and 70-40- 70L(50%). Unfortunately fresh seed has not yet been subjected to 70L, but presumably it would act much like DS seed. The requirement of light was also observed in seed of I. pseudoacorus alba from Finland. 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 2 N. C. Deno, 1993 Difficulty Moderate Rated by us, not by the source.
Start around February 21, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on February 20, 2026.
1 Clean the flesh off the seed
2 Leach in running water
Duration: 28 days
Washed and cleaned daily for 4 weeks.
3 Dry storage
Duration: 180 days · Temperature: 70°F 21°C
4 Warm moist stratification
Duration: 90 days · Temperature: 70°F 21°C · Light: dark
5 Cold moist stratification
Duration: 90 days · Temperature: 40°F 4°C
6 Warm moist stratification
Duration: 90 days · Temperature: 70°F 21°C · Light: light
about 13 months from start to step 6. Germination happens during step 6; time not stated, 21 days assumed.
71% 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. pseudoacorus (Bx) germ. 70L(55% in 2-12 w)-40-70L(9%), 40-70L(3/4), and none in 70D or 40-70D using seeds which had been DS 6 m at 70 followed by WC for 4 w. Germination was lower without the WC as shown by 70L(1/6), 70D-40-70L(5/7), 40-70L(6/1 1), and none in dark treatments. Fresh seed germ. 40-70L(50%) and 70-40- 70L(50%). Unfortunately fresh seed has not yet been subjected to 70L, but presumably it would act much like DS seed. The requirement of light was also observed in seed of I. pseudoacorus alba from Finland. 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 3 N. C. Deno, 1993 Difficulty High Rated by us, not by the source.
Start around June 18, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on June 17, 2026.
1 Clean the flesh off the seed
2 Leach in running water
Duration: 28 days
Washed and cleaned daily for 4 weeks.
3 Dry storage
Duration: 180 days · Temperature: 70°F 21°C
4 Warm moist stratification
Duration: 90 days · Temperature: 70°F 21°C · Light: light
5 Cold moist stratification
Duration: 90 days · Temperature: 40°F 4°C
6 Warm moist stratification
Duration: 90 days · Temperature: 70°F 21°C · Light: light
9 germinated in this phase.
Steps after step 4 run on after germination.
about 7 months from start to step 4. Germination happens during step 4, in 84 days.
55% germination in 14–84 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. pseudoacorus (Bx) germ. 70L(55% in 2-12 w)-40-70L(9%), 40-70L(3/4), and none in 70D or 40-70D using seeds which had been DS 6 m at 70 followed by WC for 4 w. Germination was lower without the WC as shown by 70L(1/6), 70D-40-70L(5/7), 40-70L(6/1 1), and none in dark treatments. Fresh seed germ. 40-70L(50%) and 70-40- 70L(50%). Unfortunately fresh seed has not yet been subjected to 70L, but presumably it would act much like DS seed. The requirement of light was also observed in seed of I. pseudoacorus alba from Finland. 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 4 N. C. Deno, 1993 Difficulty Moderate Rated by us, not by the source.
Start around November 17, 2026 for a May 3 last frost.
1 Clean the flesh off the seed
2 Leach in running water
Duration: 28 days
Washed and cleaned daily for 4 weeks.
3 Cold moist stratification
Duration: 90 days · Temperature: 40°F 4°C
4 Warm moist stratification
Duration: 90 days · Temperature: 70°F 21°C · Light: light
about 4 months from start to step 4. Germination happens during step 4; time not stated, 21 days assumed.
50% 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. pseudoacorus (Bx) germ. 70L(55% in 2-12 w)-40-70L(9%), 40-70L(3/4), and none in 70D or 40-70D using seeds which had been DS 6 m at 70 followed by WC for 4 w. Germination was lower without the WC as shown by 70L(1/6), 70D-40-70L(5/7), 40-70L(6/1 1), and none in dark treatments. Fresh seed germ. 40-70L(50%) and 70-40- 70L(50%). Unfortunately fresh seed has not yet been subjected to 70L, but presumably it would act much like DS seed. The requirement of light was also observed in seed of I. pseudoacorus alba from Finland. 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 5 N. C. Deno, 1993 Difficulty High Rated by us, not by the source.
Start around August 20, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on August 19, 2026.
1 Clean the flesh off the seed
2 Leach in running water
Duration: 28 days
Washed and cleaned daily for 4 weeks.
3 Warm moist stratification
Duration: 90 days · Temperature: 70°F 21°C
4 Cold moist stratification
Duration: 90 days · Temperature: 40°F 4°C
5 Warm moist stratification
Duration: 90 days · Temperature: 70°F 21°C · Light: light
about 7 months from start to step 5. Germination happens during step 5; time not stated, 21 days assumed.
50% 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. pseudoacorus (Bx) germ. 70L(55% in 2-12 w)-40-70L(9%), 40-70L(3/4), and none in 70D or 40-70D using seeds which had been DS 6 m at 70 followed by WC for 4 w. Germination was lower without the WC as shown by 70L(1/6), 70D-40-70L(5/7), 40-70L(6/1 1), and none in dark treatments. Fresh seed germ. 40-70L(50%) and 70-40- 70L(50%). Unfortunately fresh seed has not yet been subjected to 70L, but presumably it would act much like DS seed. The requirement of light was also observed in seed of I. pseudoacorus alba from Finland. 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 6 N. C. Deno, 1993 Difficulty High Rated by us, not by the source.
Start around August 20, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on August 19, 2026.
1 Clean the flesh off the seed
2 Leach in running water
Duration: 28 days
Washed and cleaned daily for 4 weeks.
3 Dry storage
Duration: 180 days · Temperature: 70°F 21°C
4 Sow and cover
Temperature: 70°F 21°C · Light: light
about 7 months from start to sowing. Germination time not stated; 21 days assumed.
17% 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. pseudoacorus (Bx) germ. 70L(55% in 2-12 w)-40-70L(9%), 40-70L(3/4), and none in 70D or 40-70D using seeds which had been DS 6 m at 70 followed by WC for 4 w. Germination was lower without the WC as shown by 70L(1/6), 70D-40-70L(5/7), 40-70L(6/1 1), and none in dark treatments. Fresh seed germ. 40-70L(50%) and 70-40- 70L(50%). Unfortunately fresh seed has not yet been subjected to 70L, but presumably it would act much like DS seed. The requirement of light was also observed in seed of I. pseudoacorus alba from Finland. 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 N. C. Deno, 1993 1 Clean the flesh off the seed
2 Leach in running water
Duration: 28 days
Washed and cleaned daily for 4 weeks.
3 Dry storage
Duration: 180 days · Temperature: 70°F 21°C
4 Sow and cover
Temperature: 70°F 21°C · Light: dark
about 7 months from start to sowing.
0% germination.
Nothing germinated at 70.
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. pseudoacorus (Bx) germ. 70L(55% in 2-12 w)-40-70L(9%), 40-70L(3/4), and none in 70D or 40-70D using seeds which had been DS 6 m at 70 followed by WC for 4 w. Germination was lower without the WC as shown by 70L(1/6), 70D-40-70L(5/7), 40-70L(6/1 1), and none in dark treatments. Fresh seed germ. 40-70L(50%) and 70-40- 70L(50%). Unfortunately fresh seed has not yet been subjected to 70L, but presumably it would act much like DS seed. The requirement of light was also observed in seed of I. pseudoacorus alba from Finland. Seed Germination Theory and Practice, 2nd ed., Ch. 20, Iris p. 156. Quoted exactly. Every value on this card comes from this record; the step names come from a fixed list. How each step is done , in Deno’s words, and what Verified and Derived mean.
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