Toxic Plant Connu comme étant toxique - Toxic to mammals if ingested.
Image of Hypericum kalmianum
Source: Donna Bos

Plant Names

image of Arbuste
Hypericum kalmianum
Kalm's St. John's-wort
Millepertuis de Kalm

Plant Characteristics

Couleur de floraison: Jaune Bloom Period: Jul - Aug
Hauteur max: 2,0 feet
Max Width: 2,0 feet (spreads by rhizome)
Light Condition:
Full sun Plus de 6 heures d'ensoleillement par jour
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: Vivace des plantes qui reviennent année après année
Gardener Experience:
beginner friendly Suitable for beginner gardeners
does not spread Ne se propage pas de manière incontrôlable
plant spread by rhizome Spreads by rhizome
plant germinate easy Facile à germer
plant self seeding Self-seeding
Landscape Uses:
rock garden Suitable for rock gardens
container suitable Suitable for container garden
school garden Suitable for school gardens
Ecological Benefits:
Bird friendly Supports birds
Tolerates:
Deer Resistant Deer resistant
Rabbit Resistant Rabbit resistant
Limestone Tolerant Tolerates limestone conditions
Sand Tolerant Tolerates sandy conditions
Acidic Soil Tolerant Tolerates acidic soil conditions
Juglone Tolerant Tolerates juglone conditions
Transplantation Tolerant Tolerates transplantation
Special Features and Considerations:

Seed and plant distribution status

No seeds available for this plant.
Nous acceptions les semences de cette plante

Faits intéressants

Kalm's St. John's-wort has masses of bright yellow blooms throughout summer. It tolerates poor soils and is excellent for foundation plantings and pollinator gardens. It provides abundant pollen for native bees, bumble bees, sweat bees, hoverflies, and beneficial insects.

Plant Location

Native to Ottawa region: Oui

Distribution according to VASCAN

Distribution: Hypericum kalmianum
Ephemeral Native Introduced Excluded Extirpated Doubtful Absent

Thrives in Ecozones

  • Plaines à forêts mixtes

Ecological Benefits

Butterflies Supported by Hypericum kalmianum

No butterfly data available for this plant.

Specialized Bees Supported by Hypericum kalmianum

No bee data available for this plant.

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 anytime
  • Stratification duration: 0 days
  • Self-seeding
  • Notes: Can be sown in late spring in warm soil.

Harvesting and Seed Sharing

  • Harvest start month: September
  • 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:
    • Pas de test requis avant le don
  • Packaging measure: 1 rounded 1/32 teaspoon
  • Seed storage:
    • Sécher à l'air dans un sac en papier ou contenant ouvert, pour quelques jours jusqu'à sec
    • Secouer de temps à autre pour prévenir la moisissure
  • Cultivar: Yes, do not donate unless you know source, and there are no known cultivars in your garden or at proximity
  • Remove non-seed material
  • No harvesting video available at this time.

Toxicity Notes

Toxic to mammals if ingested.