Mendel’s Gardens

Macleaya cordata

Plume Poppy · Five-seed Plume-poppy · Tree Celandine

Family PapaveraceaeGenus Macleaya

About the plant

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

The plant

Habit
Herbaceous perennial
Height
5-8 ft
Spread
2-4 ft
Flower
Showy; creamy white
Blooms
July to August
Native range
China, Japan, Taiwan
Hardiness zones
3-8

Growing conditions

Sun
Full sun to part shade
Soil
Moist, sandy, well-drained loam
Watering
Medium

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

Source: Plant Finder — Missouri Botanical Garden.

This source reports two treatments. Both are shown.

Protocol 1

DerivedN. C. Deno, 1993

Difficulty Moderate Rated by us, not by the source.

Start around September 10, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on September 9, 2026.

  1. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

    Deno gives no length for this period; three months is his standard cycle.

  2. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  3. Warm moist stratification

    Temperature: 70°F 21°C Light: light

    Deno moved half the seed into light a month into this third cycle; 32% followed.

about 6 months from start to sowing. Then 28 days to germinate.

32% germination in 14–28 days.

Deno calls the experiment less than ideal, but the light requirement is not in doubt.

This source doesn't state how long.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, MacleayaPublic domain
Show the original text
Macleaya (Papaveraceae). M. cordata requires light for germination. Unfortunately the experiments were not ideal. Fresh seed was subjected to 70-40-70. After a month in the 3rd cycle, halt of the seeds were shifted to light and half kept in dark. Germination was 32% in 2-4 w in light and none in the dark. The sample in the dark was then shifted to light and 32% germ. in 2-4 w as expected.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Macleaya. 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, 1993

  1. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

    Deno gives no length for this period; three months is his standard cycle.

  2. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  3. Warm moist stratification

    Temperature: 70°F 21°C Light: dark

    The half kept dark gave nothing at all.

about 6 months from start to sowing.

0% germination.

Nothing in the dark -- and the same seeds gave 32% as soon as they were moved into light.

This source doesn't state how long.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, MacleayaPublic domain
Show the original text
Macleaya (Papaveraceae). M. cordata requires light for germination. Unfortunately the experiments were not ideal. Fresh seed was subjected to 70-40-70. After a month in the 3rd cycle, halt of the seeds were shifted to light and half kept in dark. Germination was 32% in 2-4 w in light and none in the dark. The sample in the dark was then shifted to light and 32% germ. in 2-4 w as expected.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Macleaya. Quoted exactly. Every value on this card comes from this record; the step names come from a fixed list.