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Oenothera cespitosa

Tufted Evening Primrose

Family OnagraceaeGenus Oenothera

Also published as Oenothera caespitosa. You are in the right place.

White flowers opening from a rosette of toothed leaves on gravel
FlowerStan ShebsCC BY-SA 3.0

About the plant

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

Habit
perennialPlants of the World Online
Flower
WhiteFlora of North America
Native range
Alberta, Arizona, California, Colorado, Idaho, Manitoba and elsewhereGBIF Backbone Taxonomy
Note
Deno warns that seed sold under this name gives both stoloniferous and non-stoloniferous plants.Seed Germination Theory and Practice, 2nd ed.

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; Flora of North America — Flora of North America Editorial Committee; GBIF Backbone Taxonomy — Global Biodiversity Information Facility; Seed Germination Theory and Practice, 2nd ed. — N. C. Deno.

Worth knowing

  • Its flowers open at night and fade by the next day. The name evening-primrose is credited to John Goodyer, for a scent like that of Europe's wild primroses. Wikipedia: Oenothera cespitosa

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 February 1, 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 63 days to germinate.

50% germination in 14–63 days.

Four seeds of eight. Deno warns that seed sold under this name is not uniform.

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. caespitosa germ. 70L(4/8 in 2-9 w) and 70D(none). Seed sown outdoors in March germ. some in May. Seeds received under this name have given plants that are stqloniferous and others that are not. Germinations may vary.
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 Moderate Rated by us, not by the source.

Sow around March 2027 — a date the source gives, not one counted back from a May 3 last frost.

  1. Sow outdoors and leave it

    Sown outdoors in March; some up in May.

No stated waiting before sowing. Then 60 days to germinate.

Germinates in 60 days.

Sown in March, some up in May. Deno gives no count.

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. caespitosa germ. 70L(4/8 in 2-9 w) and 70D(none). Seed sown outdoors in March germ. some in May. Seeds received under this name have given plants that are stqloniferous and others that are not. Germinations may vary.
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

  1. Sow and cover

    Temperature: 70°F 21°C Light: dark

No stated waiting before sowing.

0% germination.

Nothing in the dark. This is one of the light-requiring species of the genus.

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. caespitosa germ. 70L(4/8 in 2-9 w) and 70D(none). Seed sown outdoors in March germ. some in May. Seeds received under this name have given plants that are stqloniferous and others that are not. Germinations may vary.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Oenothera. 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.

Germination trials

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

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