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Iris spuria

Blue Iris · Butterfly Iris · Seashore Iris

Family IridaceaeGenus Iris

A violet-blue iris with a yellow blaze on each hanging petal, on a stout upright stem
FlowerFranz XaverCC BY-SA 3.0

About the plant

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

The plant

Habit
Bulb, Herbaceous PerennialExtension Gardener Plant Toolbox
Habit
rhizomatous geophytePlants of the World Online
Height
2-5 ft0.6-1.5 mExtension Gardener Plant Toolbox
Spread
2-3 ft60-90 cmExtension Gardener Plant Toolbox
Flower
Blue, Purple/Lavender, Red/Burgundy, WhiteExtension Gardener Plant Toolbox
Blooms
Spring, SummerExtension Gardener Plant Toolbox
Native range
Austria, Czechia-Slovakia, Denmark, France, Germany, Hungary and elsewhereGBIF Backbone Taxonomy
Hardiness zones
5-9Extension Gardener Plant Toolbox

Growing conditions

Sun
Full sun; Partial ShadeExtension Gardener Plant Toolbox
Soil
High Organic MatterExtension Gardener Plant Toolbox
Soil pH
Neutral (6.0-8.0)Extension Gardener Plant Toolbox
Moisture
Good DrainageExtension 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

  • In Russia, digging up wild rhizomes is strictly prohibited. In Sweden it grows only on coastal meadows in the south. Wikipedia: Iris spuria

This source reports three treatments. All are shown.

Protocol 1

DerivedN. C. Deno, 1993

Difficulty Moderate Rated by us, not by the source.

Start around September 16, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on September 15, 2026.

  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 112 days.

96% germination in 21–112 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. spuria, it would probably have germ. immediately in 70L. The experiment is reported only to show how long these seeds remain viable in 70 moist. I. spuria (Bx) germ. best in 70L(92% in 7-10 w), 70D(none), 40-70L(96% in 3-16 w), and 40-70D(none). Seed DS 6 m at 70 gave similar results. All dark treatments gave less than 15% germination. I. spuria var. halophila (Bx) was received as seed DS 15 m at 70. It germ. well in the dark as shown by 70(67% in 4-9 w). It is not clear whether the difference in photoresponse between this species and the previous species was due to species difference or to longer DS times.
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

DerivedN. C. Deno, 1993

Difficulty Low Rated by us, not by the source.

Start around January 25, 2027 for a May 3 last frost.

  1. Sow and cover

    Temperature: 70°F 21°C Light: light

No stated waiting before sowing. Then 70 days to germinate.

92% germination in 49–70 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. spuria, it would probably have germ. immediately in 70L. The experiment is reported only to show how long these seeds remain viable in 70 moist. I. spuria (Bx) germ. best in 70L(92% in 7-10 w), 70D(none), 40-70L(96% in 3-16 w), and 40-70D(none). Seed DS 6 m at 70 gave similar results. All dark treatments gave less than 15% germination. I. spuria var. halophila (Bx) was received as seed DS 15 m at 70. It germ. well in the dark as shown by 70(67% in 4-9 w). It is not clear whether the difference in photoresponse between this species and the previous species was due to species difference or to longer DS times.
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

DerivedN. C. Deno, 1993

Difficulty Moderate Rated by us, not by the source.

Start around February 1, 2027 for a May 3 last frost.

  1. Sow and cover

    Temperature: 70°F 21°C

No stated waiting before sowing. Then 63 days to germinate.

67% germination in 28–63 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. spuria, it would probably have germ. immediately in 70L. The experiment is reported only to show how long these seeds remain viable in 70 moist. I. spuria (Bx) germ. best in 70L(92% in 7-10 w), 70D(none), 40-70L(96% in 3-16 w), and 40-70D(none). Seed DS 6 m at 70 gave similar results. All dark treatments gave less than 15% germination. I. spuria var. halophila (Bx) was received as seed DS 15 m at 70. It germ. well in the dark as shown by 70(67% in 4-9 w). It is not clear whether the difference in photoresponse between this species and the previous species was due to species difference or to longer DS times.
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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