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Oenothera argillicola

Shale Barren Evening Primrose

Family OnagraceaeGenus Oenothera

Two pale yellow four-petalled flowers with long curving stamens dusted in pollen, beside a slim green bud.
FlowerDoppelbrauCC BY-SA 4.0

About the plant

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

Habit
biennial or perennialPlants of the World Online
Habit
Biennial, Forb/herbPLANTS Database
Flower
Yellow, pale yellowFlora of North America
Native range
Maryland, Pennsylvania, Virginia, West VirginiaGBIF Backbone Taxonomy

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; PLANTS Database — USDA NRCS; Flora of North America — Flora of North America Editorial Committee; GBIF Backbone Taxonomy — Global Biodiversity Information Facility.

This source reports 6 treatments. All are shown.

Protocol 1

DerivedN. C. Deno, 1993

Difficulty Low Rated by us, not by the source.

Start around March 20, 2027 for a May 3 last frost.

  1. Sow on the surface — do not cover

    Temperature: 70°F 21°C Light: light

No stated waiting before sowing. Then 16 days to germinate.

86% germination in 4–16 days.

Light beats dark, GA-3 and cold. Nothing else here is needed.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, OenotheraPublic domain
Show the original text
Oenothera (Onagraceae). While many species germ. well in dark treatments, 0. biennis has an absolute light requirement so that photorequirements have to be considered in this genus. 0. argillicola germ. 70D(60% in 4d-3 w), 70L(86% in 4-16 d), 70D GA-3(83% in 2-18 d), and 40(26%)-70(51% in 2-4 d). Seeds placed Outdoors in November germ. 85% in April.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Oenothera. 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.

Sow around November 2027 — a date the source gives, not one counted back from a May 3 last frost. Too late for spring 2027 — that needed starting on November 2026.

  1. Sow outdoors and leave it

    Placed outdoors in November; up in April.

No stated waiting before sowing. Then 150 days to germinate.

85% germination in 150 days.

Out in November, up in April, 85% -- as good as the best bench treatment.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, OenotheraPublic domain
Show the original text
Oenothera (Onagraceae). While many species germ. well in dark treatments, 0. biennis has an absolute light requirement so that photorequirements have to be considered in this genus. 0. argillicola germ. 70D(60% in 4d-3 w), 70L(86% in 4-16 d), 70D GA-3(83% in 2-18 d), and 40(26%)-70(51% in 2-4 d). Seeds placed Outdoors in November germ. 85% in April.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Oenothera. 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 Low Rated by us, not by the source.

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

  1. Gibberellic acid soak

  2. Sow and cover

    Temperature: 70°F 21°C Light: dark

No stated waiting before sowing. Then 18 days to germinate.

83% germination in 2–18 days.

GA-3 substitutes for light almost exactly.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, OenotheraPublic domain
Show the original text
Oenothera (Onagraceae). While many species germ. well in dark treatments, 0. biennis has an absolute light requirement so that photorequirements have to be considered in this genus. 0. argillicola germ. 70D(60% in 4d-3 w), 70L(86% in 4-16 d), 70D GA-3(83% in 2-18 d), and 40(26%)-70(51% in 2-4 d). Seeds placed Outdoors in November germ. 85% in April.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Oenothera. 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 Low Rated by us, not by the source.

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

  1. Gibberellic acid soak

  2. Sow and cover

    Temperature: 70°F 21°C Light: dark

No stated waiting before sowing. Then 18 days to germinate.

83% germination in 2–18 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Oenothera p. 181Public domain
Show the original text
Oenothera (Onagraceae). While many species germ. well in dark treatments, 0. argillicola germ. 70D(60% in 4d-3 w), 70L(86% in 4-16 d), 70D GA-3(83% in 2-18 d), and 40(26%)-70(51% in 2-4 d). Seeds placed Outdoors in November germ. 85% in April.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Oenothera p. 181. 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 Moderate 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 Light: dark

No stated waiting before sowing. Then 21 days to germinate.

60% germination in 4–21 days.

It will germinate in the dark, at about two thirds of the lit result.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, OenotheraPublic domain
Show the original text
Oenothera (Onagraceae). While many species germ. well in dark treatments, 0. biennis has an absolute light requirement so that photorequirements have to be considered in this genus. 0. argillicola germ. 70D(60% in 4d-3 w), 70L(86% in 4-16 d), 70D GA-3(83% in 2-18 d), and 40(26%)-70(51% in 2-4 d). Seeds placed Outdoors in November germ. 85% in April.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Oenothera. 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 1, 2027 for a May 3 last frost.

  1. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

    26% germinated at 40 itself. Deno gives no length for this period; three months is his standard cycle.

  2. Warm moist stratification

    Temperature: 70°F 21°C

    A further 51%, in 2-4 days.

about 3 months from start to step 2. Germination happens during step 2, in 4 days.

51% germination in 2–4 days.

26% comes up in the cold itself, then 51% within days of the move to 70.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, OenotheraPublic domain
Show the original text
Oenothera (Onagraceae). While many species germ. well in dark treatments, 0. biennis has an absolute light requirement so that photorequirements have to be considered in this genus. 0. argillicola germ. 70D(60% in 4d-3 w), 70L(86% in 4-16 d), 70D GA-3(83% in 2-18 d), and 40(26%)-70(51% in 2-4 d). Seeds placed Outdoors in November germ. 85% in April.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Oenothera. 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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