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Hypericum prolificum

Broombush · Shrubby St. John's-wort · Shrubby St. Johnswort

Family HypericaceaeGenus Hypericum

Yellow flowers with dense tufts of stamens among narrow leaves and green buds
FlowerBananenfalterCC0

About the plant

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

The plant

Habit
Perennial, Shrub, WildflowerExtension Gardener Plant Toolbox
Habit
subshrub or shrubPlants of the World Online
Height
1-5 ft0.3-1.5 mExtension Gardener Plant Toolbox
Spread
1-4 ft0.3-1.2 mExtension Gardener Plant Toolbox
Flower
Gold/YellowExtension Gardener Plant Toolbox
Blooms
SummerExtension Gardener Plant Toolbox
Native range
Canada, lower 48 statesPLANTS Database
Hardiness zones
3-8Extension Gardener Plant Toolbox

Growing conditions

Sun
Full sun; Partial ShadeExtension Gardener Plant Toolbox
Soil
Clay, Loam (Silt), SandExtension Gardener Plant Toolbox
Soil pH
Acid (<6.0), Alkaline (>8.0), Neutral (6.0-8.0)Extension Gardener Plant Toolbox
Moisture
Good Drainage, Moist, Occasionally DryExtension Gardener Plant Toolbox
Watering
Drought tolerance: LowPLANTS Database

Toxicity is noted only where a source states it. No note here is not a finding of safety.

Sources: Extension Gardener Plant Toolbox — NC State Extension; Plants of the World Online — Royal Botanic Gardens, Kew; PLANTS Database — USDA NRCS.

Worth knowing

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

Protocol 1

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.

63% germination in 7–42 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Hypericum p. 49Public domain
Show the original text
Hypericum (Hyperiaceae). H. spathulatum seeds germ. 70L(44% in 1-7 w) and 70D(2%) for fresh seeds. Seeds DS 6 m germ. 70L(63% in 1-6 w) and 70D(7%).
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Hypericum p. 49. 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.

44% germination in 7–49 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Hypericum p. 49Public domain
Show the original text
Hypericum (Hyperiaceae). H. spathulatum seeds germ. 70L(44% in 1-7 w) and 70D(2%) for fresh seeds. Seeds DS 6 m germ. 70L(63% in 1-6 w) and 70D(7%).
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Hypericum p. 49. 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 Very high 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. Sow and cover

    Temperature: 70°F 21°C Light: dark

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

7% germination.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Hypericum p. 49Public domain
Show the original text
Hypericum (Hyperiaceae). H. spathulatum seeds germ. 70L(44% in 1-7 w) and 70D(2%) for fresh seeds. Seeds DS 6 m germ. 70L(63% in 1-6 w) and 70D(7%).
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Hypericum p. 49. 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 Very high Rated by us, not by the source.

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

  1. Sow and cover

    Temperature: 70°F 21°C Light: dark

No stated waiting before sowing. Germination time not stated; 21 days assumed.

2% germination.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Hypericum p. 49Public domain
Show the original text
Hypericum (Hyperiaceae). H. spathulatum seeds germ. 70L(44% in 1-7 w) and 70D(2%) for fresh seeds. Seeds DS 6 m germ. 70L(63% in 1-6 w) and 70D(7%).
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Hypericum p. 49. 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 Low 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 Light: dark

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

76% germination in 7–21 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Hypericum p. 154Public domain
Show the original text
Hypericum (Hyperiaceae). H. spathulatum germ. 70L(44% in 1-7 w), 70D GA-3(76%in 1-3 w), 70D(2%), 40-70L(52% in 2nd w), and 40-70D(none). Seeds placed outdoors in November germ. 27% in April. This is an unusual combination of germination patterns.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Hypericum p. 154. 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 December 22, 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

about 3 months from start to step 2. Germination happens during step 2, in 14 days.

52% germination in 14 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Hypericum p. 154Public domain
Show the original text
Hypericum (Hyperiaceae). H. spathulatum germ. 70L(44% in 1-7 w), 70D GA-3(76%in 1-3 w), 70D(2%), 40-70L(52% in 2nd w), and 40-70D(none). Seeds placed outdoors in November germ. 27% in April. This is an unusual combination of germination patterns.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Hypericum p. 154. 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

Difficulty High Rated by us, not by the source.

Sow around November 2027 — a date the source gives, not one counted back from a May 3 last frost. Too late for spring 2027 — that needed starting on November 2026.

  1. Sow outdoors and leave it

    Sown outdoors in November; up in April.

No stated waiting before sowing. Then 150 days to germinate.

27% germination in 150 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Hypericum p. 154Public domain
Show the original text
Hypericum (Hyperiaceae). H. spathulatum germ. 70L(44% in 1-7 w), 70D GA-3(76%in 1-3 w), 70D(2%), 40-70L(52% in 2nd w), and 40-70D(none). Seeds placed outdoors in November germ. 27% in April. This is an unusual combination of germination patterns.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Hypericum p. 154. 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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