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Clematis addisonii

Addison Brown's Clematis · Addison Brown's Leather-flower · Addison's Leatherflower · Addison's Leather Flower

Family RanunculaceaeGenus Clematis

Small nodding urn-shaped flowers, violet with pale recurved tips, on a vine climbing a wooden trellis
Flowerpeganum from Henfield, EnglandCC BY-SA 2.0

About the plant

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

Habit
shrubPlants of the World Online
Habit
Perennial, VinePLANTS Database
Flower
Purple, reddish purple, whitishFlora of North America
Native range
VirginiaGBIF 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; Flora of North America — Flora of North America Editorial Committee; GBIF Backbone Taxonomy — Global Biodiversity Information Facility.

Two sources report 7 treatments between them. All are shown.

Protocol 1

DerivedN. C. Deno, 1996

Difficulty Low Rated by us, not by the source.

Start around August 13, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on August 12, 2026.

  1. Dry storage

    Duration: 180 daysTemperature: 70°F 21°C

  2. Gibberellic acid soak

  3. Sow and cover

    Temperature: 70°F 21°C

about 6 months from start to sowing. Then 56 days to germinate.

100% germination in 28–56 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Clematis p. 31Public domain
Show the original text
Clematis (Ranunculaceae). C. addisonii showed a marked difference between fresh seed received in October and the same seed DS 6 m at 70. The fresh seed germ. 70 GA-3{65% in 7-11 w) and none in 70L or 70D. The DS seed germ. 70 GA-3(100% in 4-8 w), 70L(65% in 3-6 w), and 70D(50% in 9-11 w). The DS eliminates the GA-3 requirement.
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Clematis p. 31. 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 August 27, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on August 26, 2026.

  1. Dry storage

    Duration: 180 daysTemperature: 70°F 21°C

  2. Sow and cover

    Temperature: 70°F 21°C Light: light

about 6 months from start to sowing. Then 42 days to germinate.

65% germination in 21–42 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Clematis p. 31Public domain
Show the original text
Clematis (Ranunculaceae). C. addisonii showed a marked difference between fresh seed received in October and the same seed DS 6 m at 70. The fresh seed germ. 70 GA-3{65% in 7-11 w) and none in 70L or 70D. The DS seed germ. 70 GA-3(100% in 4-8 w), 70L(65% in 3-6 w), and 70D(50% in 9-11 w). The DS eliminates the GA-3 requirement.
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Clematis p. 31. 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 July 23, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on July 22, 2026.

  1. Dry storage

    Duration: 180 daysTemperature: 70°F 21°C

  2. Sow and cover

    Temperature: 70°F 21°C Light: dark

about 6 months from start to sowing. Then 77 days to germinate.

50% germination in 63–77 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Clematis p. 31Public domain
Show the original text
Clematis (Ranunculaceae). C. addisonii showed a marked difference between fresh seed received in October and the same seed DS 6 m at 70. The fresh seed germ. 70 GA-3{65% in 7-11 w) and none in 70L or 70D. The DS seed germ. 70 GA-3(100% in 4-8 w), 70L(65% in 3-6 w), and 70D(50% in 9-11 w). The DS eliminates the GA-3 requirement.
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Clematis p. 31. 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

  1. Sow and cover

    Temperature: 70°F 21°C Light: light

No stated waiting before sowing.

0% germination.

Nothing germinated at 70.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Clematis p. 31Public domain
Show the original text
Clematis (Ranunculaceae). C. addisonii showed a marked difference between fresh seed received in October and the same seed DS 6 m at 70. The fresh seed germ. 70 GA-3{65% in 7-11 w) and none in 70L or 70D. The DS seed germ. 70 GA-3(100% in 4-8 w), 70L(65% in 3-6 w), and 70D(50% in 9-11 w). The DS eliminates the GA-3 requirement.
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Clematis p. 31. Quoted exactly. Every value on this card comes from this record; 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 January 18, 2027 for a May 3 last frost.

  1. Gibberellic acid soak

  2. Sow and cover

    Temperature: 70°F 21°C Light: dark

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

65% germination in 49–77 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Clematis p. 119Public domain
Show the original text
Clematis (Ranunculaceae). Light and/or GA-3 are required for the germination of some species. Although a number of species germ. significantly in the dark, light and GA-3 needs to be tried on all species. Multicycle patterns were common and some species germ. largely at 40. The seeds of all species are designed to be dispersed by wind so that it was presumed that DS would be tolerated. This was supported by the data for seeds DS 6 m, however seeds of C. addisonii germ. 70D GA-3(65% in 7-11 w); None germ. in 70D, 70L, 40-70L, or 40-70D. Even 8 w in 70D or 3 m at 40 and a shift to 70 GA-3 led to total rotting. Seeds DS 6 m at 70 germ. 70 GA-3(60%) and none in 70D or 70L.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Clematis p. 119. 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 Moderate 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. Gibberellic acid soak

  3. Sow and cover

    Temperature: 70°F 21°C

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

60% germination.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Clematis p. 119Public domain
Show the original text
Clematis (Ranunculaceae). Light and/or GA-3 are required for the germination of some species. Although a number of species germ. significantly in the dark, light and GA-3 needs to be tried on all species. Multicycle patterns were common and some species germ. largely at 40. The seeds of all species are designed to be dispersed by wind so that it was presumed that DS would be tolerated. This was supported by the data for seeds DS 6 m, however seeds of C. addisonii germ. 70D GA-3(65% in 7-11 w); None germ. in 70D, 70L, 40-70L, or 40-70D. Even 8 w in 70D or 3 m at 40 and a shift to 70 GA-3 led to total rotting. Seeds DS 6 m at 70 germ. 70 GA-3(60%) and none in 70D or 70L.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Clematis p. 119. 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 7

DerivedN. C. Deno, 1993

  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 ed. — N. C. Deno, 1993 · Ch. 20, Clematis p. 119Public domain
Show the original text
Clematis (Ranunculaceae). Light and/or GA-3 are required for the germination of some species. Although a number of species germ. significantly in the dark, light and GA-3 needs to be tried on all species. Multicycle patterns were common and some species germ. largely at 40. The seeds of all species are designed to be dispersed by wind so that it was presumed that DS would be tolerated. This was supported by the data for seeds DS 6 m, however seeds of C. addisonii germ. 70D GA-3(65% in 7-11 w); None germ. in 70D, 70L, 40-70L, or 40-70D. Even 8 w in 70D or 3 m at 40 and a shift to 70 GA-3 led to total rotting. Seeds DS 6 m at 70 germ. 70 GA-3(60%) and none in 70D or 70L.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Clematis p. 119. 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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