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Asclepias tuberosa

Butterfly Milkweed · Butterfly-weed · Canada Root

Family ApocynaceaeGenus Asclepias

A flat head of bright orange flowers with swept-back petals, beside tight clusters of red and green buds
FlowerRagesossCC BY-SA 3.0

About the plant

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

The plant

Habit
Herbaceous Perennial, WildflowerExtension Gardener Plant Toolbox
Habit
perennialPlants of the World Online
Height
1-2 ft30-60 cmExtension Gardener Plant Toolbox
Spread
1-1.5 ft30-45 cmExtension Gardener Plant Toolbox
Flower
Gold/Yellow, Orange, Red/BurgundyExtension Gardener Plant Toolbox
Blooms
Spring, SummerExtension Gardener Plant Toolbox
Native range
Canada, lower 48 statesPLANTS Database
Hardiness zones
3-9Extension Gardener Plant Toolbox

Growing conditions

Sun
Full sun; Partial ShadeExtension Gardener Plant Toolbox
Soil
Clay, Loam (Silt), Sand, Shallow RockyExtension Gardener Plant Toolbox
Soil pH
4.8-6.8PLANTS Database
Moisture
Good Drainage, Moist, Occasionally DryExtension Gardener Plant Toolbox
Watering
Drought tolerance: HighPLANTS 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

This source reports three treatments. All are shown.

Protocol 1

DerivedN. C. Deno, 1993

Difficulty Moderate Rated by us, not by the source.

Start around December 29, 2026 for a May 3 last frost.

  1. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C Light: either

  2. Warm moist stratification

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

about 3 months from start to step 2. Germination happens during step 2, in 7 days.

100% germination in 2–7 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Asclepias p. 103Public domain
Show the original text
Asclepias (Asclepiadaceae). The four species studied have wind born seed indicating that DS is tolerated. This was generally true; but some deterioration on DS was noted in A. tuberosa germ. best in 40-70(100% in 2-7d) using either fresh seed or seed DS 6 m at 70 or 40 and less. in 70-40-70(75%). Outdoor treatment germ. 100% in March from fall sowing of fresh seed in accord with the 40-70 pattern. Light had no effect, and in particular, it did not induce immediate germination at 70. However, GA-3 treatment did effect immediate germination in 70D with 58% germ. in 4-14 d.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Asclepias p. 103. 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

Difficulty Low Rated by us, not by the source.

  1. Sow outdoors and leave it

    Up in March.

No stated waiting before sowing.

100% germination.

This source doesn't state how long step 1 lasts.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Asclepias p. 103Public domain
Show the original text
Asclepias (Asclepiadaceae). The four species studied have wind born seed indicating that DS is tolerated. This was generally true; but some deterioration on DS was noted in A. tuberosa germ. best in 40-70(100% in 2-7d) using either fresh seed or seed DS 6 m at 70 or 40 and less. in 70-40-70(75%). Outdoor treatment germ. 100% in March from fall sowing of fresh seed in accord with the 40-70 pattern. Light had no effect, and in particular, it did not induce immediate germination at 70. However, GA-3 treatment did effect immediate germination in 70D with 58% germ. in 4-14 d.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Asclepias p. 103. 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, 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. Warm moist stratification

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

  2. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C Light: either

  3. Warm moist stratification

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

about 6 months from start to step 3. Germination happens during step 3; time not stated, 21 days assumed.

75% germination.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Asclepias p. 103Public domain
Show the original text
Asclepias (Asclepiadaceae). The four species studied have wind born seed indicating that DS is tolerated. This was generally true; but some deterioration on DS was noted in A. tuberosa germ. best in 40-70(100% in 2-7d) using either fresh seed or seed DS 6 m at 70 or 40 and less. in 70-40-70(75%). Outdoor treatment germ. 100% in March from fall sowing of fresh seed in accord with the 40-70 pattern. Light had no effect, and in particular, it did not induce immediate germination at 70. However, GA-3 treatment did effect immediate germination in 70D with 58% germ. in 4-14 d.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Asclepias p. 103. 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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