Toxic Plant Known to be toxic - Toxic to mammals if ingested.
Image of Hypericum ascyron subsp. pyramidatum
Source: Donna Bos
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image of Flowering plant
Hypericum ascyron subsp. pyramidatum
American Great St. John’s-wort
Millepertuis pyramidal
No seeds available for this plant.

We are not accepting seeds for this plant at the moment.

Bloom Colour: Yellow Bloom Period: Jul - Aug
Max Height: 6.0 feet
Max Width: 4.0 feet (spreads by rhizome)
Light Condition:
Full sun More than 6 hours of direct sun a day
Part shade More than 2 or 3 hours but less than 6 hours of direct sun a day
Soil conditions:
Moisture medium Tolerates medium soil condition
Lifespan: Perennial plants that will that come back year after year
Gardener Experience:
beginner friendly Suitable for beginner gardeners
does not spread Does not spread uncontrollably
plant spread by rhizome Spreads by rhizome
plant germinate easy Easy to germinate
plant self seeding Self-seeding
Landscape Uses:
container suitable Suitable for container garden
school garden Suitable for school gardens
Ecological Benefits: No ecological benefits information available.
Tolerates:
Deer Resistant Deer resistant
Rabbit Resistant Rabbit resistant
Juglone Tolerant Tolerates juglone conditions
Transplantation Tolerant Tolerates transplantation
Special Features and Considerations:
plant endangered This plant is endangered

Plant Location

Distribution according to VASCAN

Distribution: Hypericum ascyron subsp. pyramidatum
Ephemeral Native Introduced Excluded Extirpated Doubtful Absent

Thrives in Ecozones

  • Boreal Plains
  • Mixed Wood Plains

Ecological Benefits

Butterflies Supported by Hypericum ascyron subsp. pyramidatum

No butterfly data available for this plant.

Specialized Bees Supported by Hypericum ascyron subsp. pyramidatum

No bee data available for this plant.

Plants that grow in similar conditions, that bloom at the same time.

Complementary Plants

  • No complementary plants found.

Substitute For Non-Native Plants

  • Euonymus alatus (Burning Bush)
  • Buxus sempervirens (Boxwood)
  • Forsythieae (Forsythia)
  • Berberis (Barberry)

Sowing Information

Download Seed Envelope Labels (PDF)
  • Sowing depth: Surface sow
  • Sow by February
  • Stratification duration: 60 days
  • Self-seeding

Harvesting and Seed Sharing

  • Harvest start month: November
  • Harvesting indicator:
    • Pods are brown, seeds are dark, and crisp, and little stem connecting the pod to the main stem is brown (not green)
  • Harvesting:
    • Cut stem (including pods), let air dry in paper bag, then shake seeds off after a few days
  • Seed viability test:
    • No test needed before donating
  • Packaging measure: 1 rounded 1/32 teaspoon
  • Seed storage:
    • Air dry in paper bag or open container, for a few days until crisp
    • Shake seeds to move them once in a while to prevent molding
  • Cultivar: No, you can donate without knowing the source as there are only straight species
  • Remove non-seed material
  • Harvesting video: Watch here

Toxicity Notes

Toxic to mammals if ingested.