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Hydrophyllum capitatum

Ball-head Waterleaf · Dwarf Waterleaf · Woolen-breeches · Ballhead Waterleaf

Family BoraginaceaeGenus Hydrophyllum

A rounded white flower head bristling with stamens, above divided leaves on stony ground
FlowerWalter Siegmund (talk)CC BY-SA 3.0

About the plant

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

The plant

Habit
biennial or perennialPlants of the World Online
Habit
Perennial, Forb/herbPLANTS Database
Height
1.0 ft30 cmPLANTS Database
Flower
PurplePLANTS Database
Blooms
Early SpringPLANTS Database
Native range
Canada, lower 48 statesPLANTS Database

Growing conditions

Sun
Shade tolerance: LowPLANTS Database
Soil
Adapted to medium, fine textured soilsPLANTS Database
Soil pH
6.4-7.8PLANTS Database
Moisture
Moisture use: HighPLANTS Database
Watering
Drought tolerance: LowPLANTS Database

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.

Worth knowing

This source reports three treatments. All are shown.

Protocol 1

DerivedN. C. Deno, 1996

Difficulty Moderate Rated by us, not by the source.

Start around December 22, 2026 for a May 3 last frost.

  1. Gibberellic acid soak

  2. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

  3. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

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

80% germination in 14 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Hydrophyllum p. 49Public domain
Show the original text
Hydrophyllum (Hydrophyllaceae). H. capitatum germ. 40(43% in 4-10 w) 70 GA-3-40(80% in 2nd w), and 70D-40(4%). About half the seeds died in DS 6 m 80% were dead after 2 y DS, and all were dead after 3 y DS.
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Hydrophyllum 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 January 25, 2027 for a May 3 last frost.

  1. Cold moist stratification

    Temperature: 40°F 4°C

Germination happens during step 1, in 70 days.

43% germination in 28–70 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Hydrophyllum p. 49Public domain
Show the original text
Hydrophyllum (Hydrophyllaceae). H. capitatum germ. 40(43% in 4-10 w) 70 GA-3-40(80% in 2nd w), and 70D-40(4%). About half the seeds died in DS 6 m 80% were dead after 2 y DS, and all were dead after 3 y DS.
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Hydrophyllum 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 December 15, 2026 for a May 3 last frost.

  1. Warm moist stratification

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

  2. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

about 3 months from start to step 2. Germination happens during step 2; time not stated, 21 days assumed.

4% germination.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Hydrophyllum p. 49Public domain
Show the original text
Hydrophyllum (Hydrophyllaceae). H. capitatum germ. 40(43% in 4-10 w) 70 GA-3-40(80% in 2nd w), and 70D-40(4%). About half the seeds died in DS 6 m 80% were dead after 2 y DS, and all were dead after 3 y DS.
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Hydrophyllum 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.

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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