Botanical profile

Hypericum kalmianum 'Cobalt-N-Gold'

Latin name
Hypericum kalmianum 'Cobalt-N-Gold'
Common name
Kalm's St. John's Wort 'Cobalt-N-Gold'
Type
Ornamental shrub
Family
Hypericaceae

Hypericum kalmianum ‘Cobalt-N-Gold’ is a compact and extremely decorative ornamental shrub, prized for the striking contrast between its bluish foliage and abundant bright yellow blooms. This selection stands out with its narrow, steel-blue leaves with cobalt reflections, which beautifully highlight the numerous star-shaped golden-yellow flowers with prominent stamens appearing in summer. Its overall habit is rounded, dense, and naturally well-branched, with a silhouette that is wider than it is tall, ideal for sunny borders, foreground plantings, and group plantings. The deciduous to semi-evergreen foliage, depending on the climate, provides a fine and modern texture throughout the season. Very hardy, drought-tolerant once established, and low-maintenance, ‘Cobalt-N-Gold’ is particularly well-suited for northern gardens, sustainable landscaping, and exposed sites where reliability is essential.

Care guide

Growing conditions

Light, soil, water and hardiness

Hardiness zone
Zone 4
Exposure
Sun
Watering
Low to moderate
Fertilization
Low, rarely needed
Soil type
Ordinary, well-drained, tolerates poor soils
Minimum temperature
-40°C
Plant appearance

Blooming, foliage and shape

Blooming period
Summer
Flower color
Bright yellow
Fruiting
Discrete brownish capsules of no ornamental interest
Foliage color
Steel blue with cobalt reflections
Foliage type
Deciduous to semi-evergreen
Shape
Compact, rounded, and dense shrub
Garden structure

Size and growth

Height
0.6–0.9 m (2–3 ft)
Width
3–4 ft (0.9–1.2 m)
Growth rate
Moderate
Not recommended for pets
Not recommended for pets

Pets

Pollinators
Attracts or supports pollinating insects

Pollinators

Butterflies
Plants that attract butterflies

Butterflies

Deer
Less attractive or generally tolerated by deer

Deer

The availability of our plants varies depending on arrivals, seasons, nursery production and supplier availability. Some varieties may be offered for a limited time only, depending on their natural cycle or current stock. These plant profiles are designed to guide and inspire you when choosing plants for the garden, landscaping projects, containers or long-lasting outdoor arrangements.