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Keckiella corymbosa

Redwood Keckiella

Family PlantaginaceaeGenus Keckiella

A crimson tubular flower with a swollen throat and narrow curled lips, on a leafy shrub
FlowerRuff tuff cream puffCC0

About the plant

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

Habit
subshrubPlants of the World Online
Habit
Perennial, Shrub, SubshrubPLANTS Database
Flower
Bright red, orange red, deep pinkWikipedia
Native range
CaliforniaGBIF 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; Wikipedia — Wikipedia contributors; GBIF Backbone Taxonomy — Global Biodiversity Information Facility.

Worth knowing

  • Redwood keckiella, formerly Penstemon corymbosus, is endemic to California, where it grows in the forests and chaparral of the center and north of the state. Wikipedia: Keckiella corymbosa

This source reports 6 treatments. All are shown.

Protocol 1

DerivedN. C. Deno, 1996

Difficulty Moderate Rated by us, not by the source.

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

  1. Gibberellic acid soak

  2. Sow and cover

    Temperature: 70°F 21°C

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

63% germination in 7–21 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Penstemon p. 64Public domain
Show the original text
Penstemon (Scrophulariaceae). P. corymbosus (syn. Keckiella corymbosus) germination was improved by DS 6 m at 70. The DS seed germ. 70L(50% in 1-3 w), 70D(15%), and 40(30% in 8th w). Fresh seed geim. 70D(13% in 1-11 w), 70L(40% in 1-7 w), 70 GA-3(63% in 1-3 w), and 40-70D(22% in 8th w)-70(20% on 3rd d). Seeds DS 1 y germ. 70D(35% in 2-4 w) and 70L(29% in 2-4 w).
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Penstemon p. 64. 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, 1996

Difficulty Moderate Rated by us, not by the source.

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

  1. Sow and cover

    Temperature: 70°F 21°C Light: light

No stated waiting before sowing. Then 49 days to germinate.

40% germination in 7–49 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Penstemon p. 64Public domain
Show the original text
Penstemon (Scrophulariaceae). P. corymbosus (syn. Keckiella corymbosus) germination was improved by DS 6 m at 70. The DS seed germ. 70L(50% in 1-3 w), 70D(15%), and 40(30% in 8th w). Fresh seed geim. 70D(13% in 1-11 w), 70L(40% in 1-7 w), 70 GA-3(63% in 1-3 w), and 40-70D(22% in 8th w)-70(20% on 3rd d). Seeds DS 1 y germ. 70D(35% in 2-4 w) and 70L(29% in 2-4 w).
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Penstemon p. 64. 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, 1996

Difficulty Moderate Rated by us, not by the source.

Start around March 9, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on March 8, 2026.

  1. Dry storage

    Duration: 365 daysTemperature: 70°F 21°C

  2. Sow and cover

    Temperature: 70°F 21°C Light: dark

about 12 months from start to sowing. Then 28 days to germinate.

35% germination in 14–28 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Penstemon p. 64Public domain
Show the original text
Penstemon (Scrophulariaceae). P. corymbosus (syn. Keckiella corymbosus) germination was improved by DS 6 m at 70. The DS seed germ. 70L(50% in 1-3 w), 70D(15%), and 40(30% in 8th w). Fresh seed geim. 70D(13% in 1-11 w), 70L(40% in 1-7 w), 70 GA-3(63% in 1-3 w), and 40-70D(22% in 8th w)-70(20% on 3rd d). Seeds DS 1 y germ. 70D(35% in 2-4 w) and 70L(29% in 2-4 w).
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Penstemon p. 64. 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, 1996

Difficulty High Rated by us, not by the source.

Start around March 9, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on March 8, 2026.

  1. Dry storage

    Duration: 365 daysTemperature: 70°F 21°C

  2. Sow and cover

    Temperature: 70°F 21°C Light: light

about 12 months from start to sowing. Then 28 days to germinate.

29% germination in 14–28 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Penstemon p. 64Public domain
Show the original text
Penstemon (Scrophulariaceae). P. corymbosus (syn. Keckiella corymbosus) germination was improved by DS 6 m at 70. The DS seed germ. 70L(50% in 1-3 w), 70D(15%), and 40(30% in 8th w). Fresh seed geim. 70D(13% in 1-11 w), 70L(40% in 1-7 w), 70 GA-3(63% in 1-3 w), and 40-70D(22% in 8th w)-70(20% on 3rd d). Seeds DS 1 y germ. 70D(35% in 2-4 w) and 70L(29% in 2-4 w).
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Penstemon p. 64. 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, 1996

Difficulty High Rated by us, not by the source.

Start around November 10, 2026 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 Light: dark

  3. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

    20 germinated in this phase.

Steps after step 2 run on after germination.

about 3 months from start to step 2. Germination happens during step 2, in 56 days.

22% germination in 56 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Penstemon p. 64Public domain
Show the original text
Penstemon (Scrophulariaceae). P. corymbosus (syn. Keckiella corymbosus) germination was improved by DS 6 m at 70. The DS seed germ. 70L(50% in 1-3 w), 70D(15%), and 40(30% in 8th w). Fresh seed geim. 70D(13% in 1-11 w), 70L(40% in 1-7 w), 70 GA-3(63% in 1-3 w), and 40-70D(22% in 8th w)-70(20% on 3rd d). Seeds DS 1 y germ. 70D(35% in 2-4 w) and 70L(29% in 2-4 w).
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Penstemon p. 64. 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, 1996

Difficulty High Rated by us, not by the source.

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

  1. Sow and cover

    Temperature: 70°F 21°C Light: dark

No stated waiting before sowing. Then 77 days to germinate.

13% germination in 7–77 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Penstemon p. 64Public domain
Show the original text
Penstemon (Scrophulariaceae). P. corymbosus (syn. Keckiella corymbosus) germination was improved by DS 6 m at 70. The DS seed germ. 70L(50% in 1-3 w), 70D(15%), and 40(30% in 8th w). Fresh seed geim. 70D(13% in 1-11 w), 70L(40% in 1-7 w), 70 GA-3(63% in 1-3 w), and 40-70D(22% in 8th w)-70(20% on 3rd d). Seeds DS 1 y germ. 70D(35% in 2-4 w) and 70L(29% in 2-4 w).
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Penstemon p. 64. 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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