Ames St. John’s Wort (Hypericum kalmianum ‘Ames’)

Ames St. John's Wort

The Ames St. John’s Wort (Hypericum kalmianum ‘Ames’) often commonly called Kalm St. John’s Wort, is a native evergreen shrub or sub-shrub with upright branching and lovely green foliage. Ames typically grows in a dense, tall mound 2-3 feet in height and width.

It is a neatly rounded garden shrub with dazzling golden yellow flowers in mid-summer. Ames is slightly harder than other species and has a more uniform shape and those brilliant yellow starry blossoms attract loads of butterflies and local bees. The center of each vibrant little bloom is a spray of golden sparks that are full of vital pollen and nectar resources! Must-haves for the cut flower garden, Hypericum berries are highly ornamental and look great in floral bouquets!

Flowers give way to beaked, oval, brown seed capsules that mature in fall and often persist on the shrub until spring, adding great winter interest. Hardy in the cold, Ames is tolerant down to USDA growing zone 4 and up to 7.

Planting and Application:

Use Ames as an accent, as a property-defining low hedge, for shrub borders and as backdrops to your Cottage and Perennial border! Equally adept at growing in Rock Gardens, rocky slopes, partly shaded naturalized areas, and even along pond peripheries to help secure eroding banks. Fill large hillsides and hard-to-mow slopes in dazzling yellow color and bees, and native pollinators!

St. John’s Wort makes itself right at home, even spreading out a little to form neat and tidy colonies while bridging the transition between the yard and the woods, taming the wildness and filling an area with little rays of sunshine! Don’t worry about those out-of-the-way areas attracting deer, those uninvited guests will usually leave this plant alone!

  • Golden Yellow Flowers Mid-Summer
  • Compact Uniform & Upright Form
  • Bee & Butterfly Nectar Resource & Hardy Native Cultivar
  • Glossy Ornamental & Persistent Brown Seedpods
  • Spreading & Naturalizing, Borders & Backdrops, Erosion & Accents

Tips for Care:

Ames St. John’s Wort is not particular about soil pH levels and is particularly suited for urban conditions, pollution, etc. St. John’s Wort is easy-care when grown in average, medium, well-drained soils in full sun to part shade. It prefers moist, rich, sandy loams and tolerates some drought. Deer seldom bother this plant! Just be sure to provide well-drained soils since Ames Hypericum cannot tolerate wet feet! Apply a generous 3-4 inch thick layer of mulch to retain moisture and insulate the root system from heat and winter’s chill. Prune while dormant to control the size and shape.

  • Full Sun & Some Partial Shade
  • Vigorous Growing Deciduous Flowering Shrub
  • Needs Well-Drained Soil & Moderate Moisture Needs
  • Deer Resistant & Drought Tolerance!
  • Cold-Hardy & Adaptable, Urban & Pollution Tolerant
  • Prune When Dormant

Work smarter, not harder! Hypericum shrubs practically take care of themselves!

Ames St. John’s Wort (Hypericum kalmianum ‘Ames’) Details

Common name Ames St. John's Wort
Botanical name Hypericum kalmianum 'Ames'
Plant type Deciduous
Hardiness zone 4-7
Growth rate Medium
Height 2 - 3 ft.
Width 2 - 3 ft.
Sunlight Full Sun, Partial Shade
Moisture Widely Adaptable
Soil condition Well-Drained
Pollinator-friendly Yes
Pruning time When Dormant
Flower color Yellow