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Bolboschoenus caldwellii

Caldwell's Clubrush · Sea Club-rush

Family CyperaceaeGenus Bolboschoenus

A brown spikelet cluster at the junction of two green stems against black, its bristly scales opened
FruitKevin Thiele from Perth, AustraliaCC BY 2.0

About the plant

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

Habit
perennialPlants of the World Online
Flower
Yellow-brownWikipedia
Native range
New South Wales, New Zealand North, New Zealand South, Northern Territory, Queensland, South Australia and elsewhereGBIF 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.

This source reports 4 treatments. All are shown.

Protocol 1

DerivedN. C. Deno, 1998

Difficulty Moderate Rated by us, not by the source.

Start around September 24, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on September 23, 2026.

  1. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C Light: light

  2. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  3. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C Light: light

about 6 months from start to step 3. Germination happens during step 3, in 14 days.

95% germination in 14 days.

Seed Germination Theory and Practice, 2nd Supplement — N. C. Deno, 1998 · 2nd Supplement, Bolboschoenus p. 19Public domain
Show the original text
Bolboschoenus (Cyperaceae). Both species germ. only in 40-70L and none in 70D, 70L, 70 GA-3, or OS. B. caldwellii germ. 40-70L(55% in 2-9 w)-40-70L(45% in 2nd w), 70L-40- 70L(95% in 2nd w), 70D 40-70L(76% in 1-3 w), and 40-70D-40-70L(92% in 1-3 w). T These patterns show that germination in 70L requires a prior 3 m at 40. Other prior treatments such as GA-3 had no effect.
Seed Germination Theory and Practice, 2nd Supplement, 2nd Supplement, Bolboschoenus p. 19. 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.

Start around June 19, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on June 18, 2026.

  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. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  4. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C Light: light

about 9 months from start to step 4. Germination happens during step 4, in 21 days.

92% germination in 7–21 days.

Seed Germination Theory and Practice, 2nd Supplement — N. C. Deno, 1998 · 2nd Supplement, Bolboschoenus p. 19Public domain
Show the original text
Bolboschoenus (Cyperaceae). Both species germ. only in 40-70L and none in 70D, 70L, 70 GA-3, or OS. B. caldwellii germ. 40-70L(55% in 2-9 w)-40-70L(45% in 2nd w), 70L-40- 70L(95% in 2nd w), 70D 40-70L(76% in 1-3 w), and 40-70D-40-70L(92% in 1-3 w). T These patterns show that germination in 70L requires a prior 3 m at 40. Other prior treatments such as GA-3 had no effect.
Seed Germination Theory and Practice, 2nd Supplement, 2nd Supplement, Bolboschoenus p. 19. 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 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. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C Light: dark

  2. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  3. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C Light: light

about 6 months from start to step 3. Germination happens during step 3, in 21 days.

76% germination in 7–21 days.

Seed Germination Theory and Practice, 2nd Supplement — N. C. Deno, 1998 · 2nd Supplement, Bolboschoenus p. 19Public domain
Show the original text
Bolboschoenus (Cyperaceae). Both species germ. only in 40-70L and none in 70D, 70L, 70 GA-3, or OS. B. caldwellii germ. 40-70L(55% in 2-9 w)-40-70L(45% in 2nd w), 70L-40- 70L(95% in 2nd w), 70D 40-70L(76% in 1-3 w), and 40-70D-40-70L(92% in 1-3 w). T These patterns show that germination in 70L requires a prior 3 m at 40. Other prior treatments such as GA-3 had no effect.
Seed Germination Theory and Practice, 2nd Supplement, 2nd Supplement, Bolboschoenus p. 19. 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 November 3, 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: light

  3. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  4. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C Light: light

    45 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 63 days.

55% germination in 14–63 days.

Seed Germination Theory and Practice, 2nd Supplement — N. C. Deno, 1998 · 2nd Supplement, Bolboschoenus p. 19Public domain
Show the original text
Bolboschoenus (Cyperaceae). Both species germ. only in 40-70L and none in 70D, 70L, 70 GA-3, or OS. B. caldwellii germ. 40-70L(55% in 2-9 w)-40-70L(45% in 2nd w), 70L-40- 70L(95% in 2nd w), 70D 40-70L(76% in 1-3 w), and 40-70D-40-70L(92% in 1-3 w). T These patterns show that germination in 70L requires a prior 3 m at 40. Other prior treatments such as GA-3 had no effect.
Seed Germination Theory and Practice, 2nd Supplement, 2nd Supplement, Bolboschoenus p. 19. 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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