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Primula frondosa

Leafy Primrose

Family PrimulaceaeGenus Primula

A flat rosette of leaves mealy white beneath, with pink yellow-eyed flowers on short stalks, growing among gray scree.
The whole plantGhislain118 http://www.fleurs-des-montagnes.netCC 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
PinkWikipedia
Native range
BulgariaGBIF 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; Wikipedia — Wikipedia contributors; GBIF Backbone Taxonomy — Global Biodiversity Information Facility.

Worth knowing

  • The leafy primrose grows only in a small part of the central Balkan Mountains of Bulgaria, in shady places at 800 to 2,200 m, within the Central Balkan National Park and nearby nature reserves. Wikipedia: Primula frondosa

This source reports 5 treatments. All are shown.

Protocol 1

DerivedN. C. Deno, 1993

Difficulty Moderate Rated by us, not by the source.

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

  1. Sow and cover

    Temperature: 70°F 21°C

No stated waiting before sowing. Then 35 days to germinate.

46% germination in 14–35 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Primula p. 197Public domain
Show the original text
Primula. (Primulaceae). The discovery of a photorequirement in P. frondosa (F) is the most vigorous :of the farinosa variants. Fresh seed germ. 70(46% in 2-5 w) and less than 1% at 40. Seed DS 6 m at 70 germ. 70-40-70(42% in 5-9 d) and none at 40. Seed DS 6 m at 40 germ. 70(10%) and 40(25%).
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Primula p. 197. 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 April 2, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on April 1, 2026.

  1. Dry storage

    Duration: 180 daysTemperature: 70°F 21°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

about 12 months from start to step 4. Germination happens during step 4, in 9 days.

42% germination in 5–9 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Primula p. 197Public domain
Show the original text
Primula. (Primulaceae). The discovery of a photorequirement in P. frondosa (F) is the most vigorous :of the farinosa variants. Fresh seed germ. 70(46% in 2-5 w) and less than 1% at 40. Seed DS 6 m at 70 germ. 70-40-70(42% in 5-9 d) and none at 40. Seed DS 6 m at 40 germ. 70(10%) and 40(25%).
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Primula p. 197. 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 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

    Temperature: 40°F 4°C

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

25% germination.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Primula p. 197Public domain
Show the original text
Primula. (Primulaceae). The discovery of a photorequirement in P. frondosa (F) is the most vigorous :of the farinosa variants. Fresh seed germ. 70(46% in 2-5 w) and less than 1% at 40. Seed DS 6 m at 70 germ. 70-40-70(42% in 5-9 d) and none at 40. Seed DS 6 m at 40 germ. 70(10%) and 40(25%).
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Primula p. 197. 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 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. Sow and cover

    Temperature: 70°F 21°C

about 6 months from start to sowing. Germination time not stated; 21 days assumed.

10% germination.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Primula p. 197Public domain
Show the original text
Primula. (Primulaceae). The discovery of a photorequirement in P. frondosa (F) is the most vigorous :of the farinosa variants. Fresh seed germ. 70(46% in 2-5 w) and less than 1% at 40. Seed DS 6 m at 70 germ. 70-40-70(42% in 5-9 d) and none at 40. Seed DS 6 m at 40 germ. 70(10%) and 40(25%).
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Primula p. 197. 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

  1. Cold moist stratification

    Temperature: 40°F 4°C

Germination happens during step 1.

0% germination.

Nothing germinated at 40.

This source doesn't state how long step 1 lasts.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Primula p. 197Public domain
Show the original text
Primula. (Primulaceae). The discovery of a photorequirement in P. frondosa (F) is the most vigorous :of the farinosa variants. Fresh seed germ. 70(46% in 2-5 w) and less than 1% at 40. Seed DS 6 m at 70 germ. 70-40-70(42% in 5-9 d) and none at 40. Seed DS 6 m at 40 germ. 70(10%) and 40(25%).
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Primula p. 197. 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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