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Penstemon crandallii

Crandall's Beardtongue

Family PlantaginaceaeGenus Penstemon

Violet two-lipped flowers with pale throats, opening from a spike of green buds on a stem of narrow leaves, with aspen trunks behind.
FlowerCecelia Alexander https://www.inaturalist.org/people/aspidoscelisCC0

About the plant

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

Habit
subshrubPlants of the World Online
Habit
Perennial, Forb/herb, SubshrubPLANTS Database
Flower
Blue, purpleWikipedia
Native range
Native to the lower 48 statesPLANTS Database

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; Wikipedia — Wikipedia contributors.

Worth knowing

  • Named for Charles Spencer Crandall, a professor at what eventually became Colorado State University. Crossed with Penstemon linarioides var. coloradensis, it gave the cultivar 'Blue Lips'. Wikipedia: Penstemon crandallii

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 August 6, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on August 5, 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, in 63 days.

86% germination in 35–63 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Penstemon p. 187Public domain
Show the original text
Penstemon (Scrophulariaceae). Four types of germination were observed. Most Rocky Mountain species of a perennial nature germ. largely at 40 and often sowing at 70 was fatal or near fatal. A second group are short lived species that can flower the first year from seed typified by P. glabrescens germ. 40(86% in 5-9 w) and 70(8%)-40(58% in 3-12 w)-70(4%) using seed DS 6 m at 70 and 40(84% in 5-12 w)-70(5%) and 70(2%)-40(2%) using fresh seed.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Penstemon p. 187. 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.

Start around January 11, 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

    5 germinated in this phase.

Steps after step 1 run on after germination.

Germination happens during step 1, in 84 days.

84% germination in 35–84 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Penstemon p. 187Public domain
Show the original text
Penstemon (Scrophulariaceae). Four types of germination were observed. Most Rocky Mountain species of a perennial nature germ. largely at 40 and often sowing at 70 was fatal or near fatal. A second group are short lived species that can flower the first year from seed typified by P. glabrescens germ. 40(86% in 5-9 w) and 70(8%)-40(58% in 3-12 w)-70(4%) using seed DS 6 m at 70 and 40(84% in 5-12 w)-70(5%) and 70(2%)-40(2%) using fresh seed.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Penstemon p. 187. 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 April 17, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on April 16, 2026.

  1. Dry storage

    Duration: 180 daysTemperature: 70°F 21°C

  2. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

    8 germinated in this phase.

  3. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  4. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

    4 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, in 84 days.

58% germination in 21–84 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Penstemon p. 187Public domain
Show the original text
Penstemon (Scrophulariaceae). Four types of germination were observed. Most Rocky Mountain species of a perennial nature germ. largely at 40 and often sowing at 70 was fatal or near fatal. A second group are short lived species that can flower the first year from seed typified by P. glabrescens germ. 40(86% in 5-9 w) and 70(8%)-40(58% in 3-12 w)-70(4%) using seed DS 6 m at 70 and 40(84% in 5-12 w)-70(5%) and 70(2%)-40(2%) using fresh seed.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Penstemon p. 187. 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 Moderate Rated by us, not by the source.

Start around October 14, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on October 13, 2026.

  1. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

  2. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

about 3 months from start to step 2. Germination happens during step 2, in 84 days.

45% germination in 28–84 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Penstemon p. 187Public domain
Show the original text
Penstemon (Scrophulariaceae). Four types of germination were observed. Most Rocky Mountain species of a perennial nature germ. largely at 40 and often sowing at 70 was fatal or near fatal. A second group are short lived species that can flower the first year from seed typified by P. crandalli germ. 70-40(45% in 4-12 w) and 40(3%)-70(30% in 3-25 d).
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Penstemon p. 187. 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 December 11, 2026 for a May 3 last frost.

  1. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

    3 germinated in this phase.

  2. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

about 3 months from start to step 2. Germination happens during step 2, in 25 days.

30% germination in 3–25 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Penstemon p. 187Public domain
Show the original text
Penstemon (Scrophulariaceae). Four types of germination were observed. Most Rocky Mountain species of a perennial nature germ. largely at 40 and often sowing at 70 was fatal or near fatal. A second group are short lived species that can flower the first year from seed typified by P. crandalli germ. 70-40(45% in 4-12 w) and 40(3%)-70(30% in 3-25 d).
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Penstemon p. 187. 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 Very high Rated by us, not by the source.

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

  1. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

  2. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

    2 germinated in this phase.

Steps after step 1 run on after germination.

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

2% germination.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Penstemon p. 187Public domain
Show the original text
Penstemon (Scrophulariaceae). Four types of germination were observed. Most Rocky Mountain species of a perennial nature germ. largely at 40 and often sowing at 70 was fatal or near fatal. A second group are short lived species that can flower the first year from seed typified by P. glabrescens germ. 40(86% in 5-9 w) and 70(8%)-40(58% in 3-12 w)-70(4%) using seed DS 6 m at 70 and 40(84% in 5-12 w)-70(5%) and 70(2%)-40(2%) using fresh seed.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Penstemon p. 187. 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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