Kalm's St. John's wort (Hypericum kalmianum)
Care, watering, light and tips for Kalm's St. John's wort on Floravia.
Quick facts
- Family: Hypericaceae
- Difficulty: Easy to care for
- Watering: every 7 days
- Light: Partial shade
- Temperature: 10–30 °C
- Toxicity: Toxic to pets
About Kalm's St. John's wort
Hypericum kalmianum, commonly known as Kalm's St. John's Wort, is a compact deciduous shrub cherished for its profuse bright yellow blooms in late summer. Its delicate five-petaled flowers with prominent stamens make it ideal for borders, rock gardens, or as an accent plant in small spaces. Its bluish-green foliage adds textural interest even when not in bloom.
Native range
Eastern North America
Care tips
It thrives in full sun for optimal flowering, though it can tolerate some partial shade. It requires well-drained, sandy or loamy soil and is quite drought-tolerant once established, though regular watering during dry spells will promote better growth. Avoid waterlogging, as it is susceptible to root rot. Light pruning after flowering can maintain its shape and encourage denser blooming the following year.