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Hypericum ascyron (Great St. John’s Wort)

Great St. John's Wort, Giant St. John's Wort, Hypericum pyramidatum

Hypericum ascyron, Great St. John's Wort, Giant St. John's Wort, Hypericum pyramidatum, Yellow Shrub, yellow flowers

Robust and easy to grow, Hypericum ascyron (Great St. John’s Wort) is an upright perennial boasting showy, bright yellow flowers, 2 in. wide (5 cm), adorned with a prominent bouquet of yellow stamens. Blooming for about 2-3 weeks in early to late summer, the blossoms are borne in pyramidal clusters atop stout, erect stems clad with large, elliptic leaves, 5 in. long (12 cm). They give way to ornamental seed pods which persist into winter. Great St. John’s Wort is suitable for the back of the perennial border, woodland margins or slopes.

  • Grows up to 2-5 ft. tall (60-150 cm) and 1-3 ft. wide (30-90cm). Will spread by rhizomes to form small colonies.
  • A full sun to part shade lover, this plant is easily grown in moist, well-drained soils.
  • Perfect for banks and slopes or mixed borders.
  • No serious pest or disease issues.
  • Native to North America, eastern Asia.

Requirements

Hardiness 4 - 8
Plant Type Perennials
Plant Family Hypericaceae
Genus Hypericum
Common names St. John's Wort
Exposure Full Sun, Partial Sun
Season of Interest Summer (Early, Mid, Late)
Height 2' - 5'
(60cm - 150cm)
Spread 1' - 3'
(30cm - 90cm)
Spacing 24" - 36"
(60cm - 90cm)
Maintenance Low
Water Needs Average
Soil Type Chalk, Clay, Loam, Sand
Soil pH Acid, Alkaline, Neutral
Soil Drainage Moist but Well-Drained
Characteristics Showy
Native Plants United States, Northeast, Pennsylvania, Vermont, Connecticut, Delaware, Maine, Massachusetts, Maryland, New Hampshire, New Jersey, New York, Kansas, Midwest, Minnesota, Missouri, Indiana, Illinois, Nebraska, Michigan, Ohio, Iowa, Wisconsin, Southeast, West Virginia
Garden Uses Banks And Slopes, Beds And Borders
Garden Styles Informal and Cottage, Prairie and Meadow
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Alternative Plants to Consider

Hypericum densiflorum (Bushy St. John’s Wort)
Hypericum prolificum (Shrubby St. John’s Wort)
Hypericum frondosum ‘Sunburst’ (St. John’s Wort)
Hypericum x moserianum ‘Tricolor’ (St. John’s Wort)
Hypericum x hidcoteense ‘Hidcote’ (St. John’s Wort)
Hypericum kalmianum Cobalt-n-Gold™ (Kalm St. John’s Wort)

Recommended Companion Plants

Silphium perfoliatum (Cup Plant)
Asclepias incarnata (Swamp Milkweed)
Eupatorium maculatum (Spotted Joe-Pye Weed)
Zizia aurea (Golden Alexanders)
Rudbeckia hirta (Black-Eyed Susan)
Veronicastrum virginicum (Culver’s Root)
While every effort has been made to describe these plants accurately, please keep in mind that height, bloom time, and color may differ in various climates. The description of these plants has been written based on numerous outside resources.
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Requirements

Hardiness 4 - 8
Plant Type Perennials
Plant Family Hypericaceae
Genus Hypericum
Common names St. John's Wort
Exposure Full Sun, Partial Sun
Season of Interest Summer (Early, Mid, Late)
Height 2' - 5'
(60cm - 150cm)
Spread 1' - 3'
(30cm - 90cm)
Spacing 24" - 36"
(60cm - 90cm)
Maintenance Low
Water Needs Average
Soil Type Chalk, Clay, Loam, Sand
Soil pH Acid, Alkaline, Neutral
Soil Drainage Moist but Well-Drained
Characteristics Showy
Native Plants United States, Northeast, Pennsylvania, Vermont, Connecticut, Delaware, Maine, Massachusetts, Maryland, New Hampshire, New Jersey, New York, Kansas, Midwest, Minnesota, Missouri, Indiana, Illinois, Nebraska, Michigan, Ohio, Iowa, Wisconsin, Southeast, West Virginia
Garden Uses Banks And Slopes, Beds And Borders
Garden Styles Informal and Cottage, Prairie and Meadow
How Many Plants
Do I Need?
Not sure which Hypericum (St. John's Wort) to pick?
Compare Now

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