Deno’s Garden

Penstemon cyathophorus

Genus Penstemon

This source reports 5 treatments. All are shown.

Protocol 1

DerivedN. C. Deno, 1998

Difficulty Low Rated by us, not by the source.

Start around March 8, 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 28 days to germinate.

100% germination in 14–28 days.

Seed Germination Theory and Practice, 2nd Supplement — N. C. Deno, 1998 · 2nd Supplement, Penstemon p. 52Public domain
Show the original text
Penstemon (Scrophulariaceae). Some of the following data are updates on species reported in the 1st Suppl. As noted in the 2nd Ed. and 1st Suppl., 'there is a wide range of germination behaviors in this genus ranging from requirements for light, oscillating temperatures, low temperatures, and GA-3. P. cyathophorus germ. 70 GA-3(100% in 2-4 w), 40(1/9 8th w), OT(8/12 in March-April), and none in 70D or 70L. Seeds DS 2 y germ. 40-70(3/14 on 3rd d) and 70(none).
Seed Germination Theory and Practice, 2nd Supplement, 2nd Supplement, Penstemon p. 52. 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, 1998

Difficulty Moderate Rated by us, not by the source.

  1. Sow outdoors and leave it

    Up in March-April.

No stated waiting before sowing.

67% germination.

This source doesn't state how long.

Seed Germination Theory and Practice, 2nd Supplement — N. C. Deno, 1998 · 2nd Supplement, Penstemon p. 52Public domain
Show the original text
Penstemon (Scrophulariaceae). Some of the following data are updates on species reported in the 1st Suppl. As noted in the 2nd Ed. and 1st Suppl., 'there is a wide range of germination behaviors in this genus ranging from requirements for light, oscillating temperatures, low temperatures, and GA-3. P. cyathophorus germ. 70 GA-3(100% in 2-4 w), 40(1/9 8th w), OT(8/12 in March-April), and none in 70D or 70L. Seeds DS 2 y germ. 40-70(3/14 on 3rd d) and 70(none).
Seed Germination Theory and Practice, 2nd Supplement, 2nd Supplement, Penstemon p. 52. 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, 1998

Difficulty High Rated by us, not by the source.

Start around October 5, 2026 for a May 3 last frost. Too late for spring 2027 — that needed starting on October 4, 2024.

  1. Dry storage

    Duration: 730 daysTemperature: 70°F 21°C

  2. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  3. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

about 2.5 years from start to sowing. Then 3 days to germinate.

21% germination in 3 days.

Seed Germination Theory and Practice, 2nd Supplement — N. C. Deno, 1998 · 2nd Supplement, Penstemon p. 52Public domain
Show the original text
Penstemon (Scrophulariaceae). Some of the following data are updates on species reported in the 1st Suppl. As noted in the 2nd Ed. and 1st Suppl., 'there is a wide range of germination behaviors in this genus ranging from requirements for light, oscillating temperatures, low temperatures, and GA-3. P. cyathophorus germ. 70 GA-3(100% in 2-4 w), 40(1/9 8th w), OT(8/12 in March-April), and none in 70D or 70L. Seeds DS 2 y germ. 40-70(3/14 on 3rd d) and 70(none).
Seed Germination Theory and Practice, 2nd Supplement, 2nd Supplement, Penstemon p. 52. 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, 1998

Difficulty High Rated by us, not by the source.

Start around February 8, 2027 for a May 3 last frost.

  1. Cold moist stratification

    Temperature: 40°F 4°C

No stated waiting before sowing. Then 56 days to germinate.

11% germination in 56 days.

This source doesn't state how long.

Seed Germination Theory and Practice, 2nd Supplement — N. C. Deno, 1998 · 2nd Supplement, Penstemon p. 52Public domain
Show the original text
Penstemon (Scrophulariaceae). Some of the following data are updates on species reported in the 1st Suppl. As noted in the 2nd Ed. and 1st Suppl., 'there is a wide range of germination behaviors in this genus ranging from requirements for light, oscillating temperatures, low temperatures, and GA-3. P. cyathophorus germ. 70 GA-3(100% in 2-4 w), 40(1/9 8th w), OT(8/12 in March-April), and none in 70D or 70L. Seeds DS 2 y germ. 40-70(3/14 on 3rd d) and 70(none).
Seed Germination Theory and Practice, 2nd Supplement, 2nd Supplement, Penstemon p. 52. 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, 1998

  1. Sow and cover

    Temperature: 70°F 21°C Light: dark

No stated waiting before sowing.

0% germination.

Nothing germinated at 70.

Seed Germination Theory and Practice, 2nd Supplement — N. C. Deno, 1998 · 2nd Supplement, Penstemon p. 52Public domain
Show the original text
Penstemon (Scrophulariaceae). Some of the following data are updates on species reported in the 1st Suppl. As noted in the 2nd Ed. and 1st Suppl., 'there is a wide range of germination behaviors in this genus ranging from requirements for light, oscillating temperatures, low temperatures, and GA-3. P. cyathophorus germ. 70 GA-3(100% in 2-4 w), 40(1/9 8th w), OT(8/12 in March-April), and none in 70D or 70L. Seeds DS 2 y germ. 40-70(3/14 on 3rd d) and 70(none).
Seed Germination Theory and Practice, 2nd Supplement, 2nd Supplement, Penstemon p. 52. Quoted exactly. Every value on this card comes from this record; the step names come from a fixed list.