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Iris graeberiana

Graeber's Juno

Family IridaceaeGenus Iris

A clump of pale blue irises standing above broad glossy strap leaves in a bare garden bed
The whole plantAlex HaunerCC BY-SA 4.0

About the plant

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

Habit
tuberous geophytePlants of the World Online
Flower
MauveWikipedia

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

Sources: Plants of the World Online — Royal Botanic Gardens, Kew; Wikipedia — Wikipedia contributors.

Worth knowing

  • Named after Paul Graeber, a plant collector who also collected Iris hoogiana and Tulipa ostrowskiana for the Dutch Van Tubergen company. One of the more vigorous species, it is easier to grow than others in its subgenus. Wikipedia: Iris graeberiana

This source reports 7 treatments. All are shown.

Protocol 1

DerivedN. C. Deno, 1993

Difficulty Moderate Rated by us, not by the source.

Start around July 23, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on July 22, 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

about 6 months from start to step 3. Germination happens during step 3, in 77 days.

91% germination in 42–77 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Juno p. 162Public domain
Show the original text
Juno (lridaceae). This genus has been separated from Iris, and this separation is adopted here. Germination can extend over periods as long as 4 y and probably more. Treatment with GA-3 has not as yet initiated germination. J. graeberiana germ. best with fresh seed in 40-70-40(10/11 in 6-11 w) and nearly as well in 7040(5/12)-70-40(2/12). Germination was more extended with DS seed. Seed DS 6 m at 70 germ. 40(3/20)-70(1/20)-40-70-40(2/20)-70-40..70(2/20) and 70-40-70-40-70-40(1/20). Seed DS 6 m at 40 germ. 40-70(2/14)-40(3/14)-70- 40(2/14)-70(1/14)-40-70 and 70-40(4/14)-70(1/14)-40(2/14)-70-40-70-40(2/14)-70-40- 70-40(2/14). Several seeds germ. after 4 y of alternating cycles and appeared to be normal and, healthy.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Juno p. 162. 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, 1993

Difficulty High Rated by us, not by the source.

Start around March 15, 2027 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

  3. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

    2/12 germinated in this phase.

Steps after step 1 run on after germination.

Germination happens during step 1; time not stated, 21 days assumed.

42% germination.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Juno p. 162Public domain
Show the original text
Juno (lridaceae). This genus has been separated from Iris, and this separation is adopted here. Germination can extend over periods as long as 4 y and probably more. Treatment with GA-3 has not as yet initiated germination. J. graeberiana germ. best with fresh seed in 40-70-40(10/11 in 6-11 w) and nearly as well in 7040(5/12)-70-40(2/12). Germination was more extended with DS seed. Seed DS 6 m at 70 germ. 40(3/20)-70(1/20)-40-70-40(2/20)-70-40..70(2/20) and 70-40-70-40-70-40(1/20). Seed DS 6 m at 40 germ. 40-70(2/14)-40(3/14)-70- 40(2/14)-70(1/14)-40-70 and 70-40(4/14)-70(1/14)-40(2/14)-70-40-70-40(2/14)-70-40- 70-40(2/14). Several seeds germ. after 4 y of alternating cycles and appeared to be normal and, healthy.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Juno p. 162. 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, 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. Dry storage

    Duration: 180 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

    1/14 germinated in this phase.

  5. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

    2/14 germinated in this phase.

  6. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

  7. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  8. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

  9. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

    2/14 germinated in this phase.

  10. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

  11. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  12. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

  13. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

    2/14 germinated in this phase.

Steps after step 3 run on after germination.

about 9 months from start to step 3. Germination happens during step 3; time not stated, 21 days assumed.

29% germination.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Juno p. 162Public domain
Show the original text
Juno (lridaceae). This genus has been separated from Iris, and this separation is adopted here. Germination can extend over periods as long as 4 y and probably more. Treatment with GA-3 has not as yet initiated germination. J. graeberiana germ. best with fresh seed in 40-70-40(10/11 in 6-11 w) and nearly as well in 7040(5/12)-70-40(2/12). Germination was more extended with DS seed. Seed DS 6 m at 70 germ. 40(3/20)-70(1/20)-40-70-40(2/20)-70-40..70(2/20) and 70-40-70-40-70-40(1/20). Seed DS 6 m at 40 germ. 40-70(2/14)-40(3/14)-70- 40(2/14)-70(1/14)-40-70 and 70-40(4/14)-70(1/14)-40(2/14)-70-40-70-40(2/14)-70-40- 70-40(2/14). Several seeds germ. after 4 y of alternating cycles and appeared to be normal and, healthy.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Juno p. 162. 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, 1993

Difficulty High Rated by us, not by the source.

Start around March 21, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on March 20, 2026.

  1. Dry storage

    Duration: 180 daysTemperature: 40°F 4°C

  2. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  3. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

    2/14 germinated in this phase.

  4. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  5. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

  6. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

    2/14 germinated in this phase.

  7. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

    1/14 germinated in this phase.

  8. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  9. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

Steps after step 4 run on after germination.

about 12 months from start to step 4. Germination happens during step 4; time not stated, 21 days assumed.

21% germination.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Juno p. 162Public domain
Show the original text
Juno (lridaceae). This genus has been separated from Iris, and this separation is adopted here. Germination can extend over periods as long as 4 y and probably more. Treatment with GA-3 has not as yet initiated germination. J. graeberiana germ. best with fresh seed in 40-70-40(10/11 in 6-11 w) and nearly as well in 7040(5/12)-70-40(2/12). Germination was more extended with DS seed. Seed DS 6 m at 70 germ. 40(3/20)-70(1/20)-40-70-40(2/20)-70-40..70(2/20) and 70-40-70-40-70-40(1/20). Seed DS 6 m at 40 germ. 40-70(2/14)-40(3/14)-70- 40(2/14)-70(1/14)-40-70 and 70-40(4/14)-70(1/14)-40(2/14)-70-40-70-40(2/14)-70-40- 70-40(2/14). Several seeds germ. after 4 y of alternating cycles and appeared to be normal and, healthy.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Juno p. 162. 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, 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. Dry storage

    Duration: 180 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

    1/20 germinated in this phase.

  4. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  5. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

  6. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

    2/20 germinated in this phase.

  7. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

  8. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

Steps after step 2 run on after germination.

about 6 months from start to step 2. Germination happens during step 2; time not stated, 21 days assumed.

15% germination.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Juno p. 162Public domain
Show the original text
Juno (lridaceae). This genus has been separated from Iris, and this separation is adopted here. Germination can extend over periods as long as 4 y and probably more. Treatment with GA-3 has not as yet initiated germination. J. graeberiana germ. best with fresh seed in 40-70-40(10/11 in 6-11 w) and nearly as well in 7040(5/12)-70-40(2/12). Germination was more extended with DS seed. Seed DS 6 m at 70 germ. 40(3/20)-70(1/20)-40-70-40(2/20)-70-40..70(2/20) and 70-40-70-40-70-40(1/20). Seed DS 6 m at 40 germ. 40-70(2/14)-40(3/14)-70- 40(2/14)-70(1/14)-40-70 and 70-40(4/14)-70(1/14)-40(2/14)-70-40-70-40(2/14)-70-40- 70-40(2/14). Several seeds germ. after 4 y of alternating cycles and appeared to be normal and, healthy.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Juno p. 162. 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 High Rated by us, not by the source.

Start around March 15, 2027 for a May 3 last frost.

  1. Sow and cover

    Temperature: 70°F 21°C

No stated waiting before sowing. Germination time not stated; 21 days assumed.

10% germination.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Juno p. 162Public domain
Show the original text
Juno (lridaceae). This genus has been separated from Iris, and this separation is adopted here. Germination can extend over periods as long as 4 y and probably more. Treatment with GA-3 has not as yet initiated germination. J. graeberiana germ. best with fresh seed in 40-70-40(10/11 in 6-11 w) and nearly as well in 7040(5/12)-70-40(2/12). Germination was more extended with DS seed. Seed DS 6 m at 70 germ. 40(3/20)-70(1/20)-40-70-40(2/20)-70-40..70(2/20) and 70-40-70-40-70-40(1/20). Seed DS 6 m at 40 germ. 40-70(2/14)-40(3/14)-70- 40(2/14)-70(1/14)-40-70 and 70-40(4/14)-70(1/14)-40(2/14)-70-40-70-40(2/14)-70-40- 70-40(2/14). Several seeds germ. after 4 y of alternating cycles and appeared to be normal and, healthy.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Juno p. 162. 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 Very high Rated by us, not by the source.

Start around December 21, 2026 for a May 3 last frost. Too late for spring 2027 — that needed starting on December 20, 2025.

  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

  6. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

about 15 months from start to step 6. Germination happens during step 6; time not stated, 21 days assumed.

5% germination.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Juno p. 162Public domain
Show the original text
Juno (lridaceae). This genus has been separated from Iris, and this separation is adopted here. Germination can extend over periods as long as 4 y and probably more. Treatment with GA-3 has not as yet initiated germination. J. graeberiana germ. best with fresh seed in 40-70-40(10/11 in 6-11 w) and nearly as well in 7040(5/12)-70-40(2/12). Germination was more extended with DS seed. Seed DS 6 m at 70 germ. 40(3/20)-70(1/20)-40-70-40(2/20)-70-40..70(2/20) and 70-40-70-40-70-40(1/20). Seed DS 6 m at 40 germ. 40-70(2/14)-40(3/14)-70- 40(2/14)-70(1/14)-40-70 and 70-40(4/14)-70(1/14)-40(2/14)-70-40-70-40(2/14)-70-40- 70-40(2/14). Several seeds germ. after 4 y of alternating cycles and appeared to be normal and, healthy.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Juno p. 162. 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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