Species Native to Missouri
Common Name: round fruited St. John's wort
Type: Herbaceous perennial
Family: Hypericaceae
Native Range: Central North America
Zone: 5 to 8
Height: 1.50 to 2.50 feet
Spread: 1.50 to 2.50 feet
Bloom Time: June to July
Bloom Description: Yellow
Sun: Full sun to part shade
Water: Dry to medium
Maintenance: Low
Flower: Showy, Fragrant
Tolerate: Drought, Dry Soil
Culture
Easily grown in dry to medium moisture soils in full sun to part shade. Tolerates a wide variety of soils, including those with significant amounts of clay, sand or gravel. Also tolerates wide fluxuations in soil moisture ranging from periods of drought to periods of swampy conditions. Spreads by rhizomes and self-seeding,
Noteworthy Characteristics
Hypericum sphaerocarpum, commonly known as round-fruited St. John’s wort or round-seeded St. John’s wort, is a shrub-like, woody based perennial that typically grows to 2 1/2’ tall. Upper stems are herbaceous. It is native to North America ranging from Ontario, Pennsylvania, Michigan and Nebraska south to Georgia and Texas. Habitats include mesic to dry gravel prairies, sand prairies, hill prairies, rocky open woodlands, thickets, scrubby barrens, rocky bluffs, limestone glades, dry banks of lakes, and open areas along roads. Linear-oblong to elliptic leaves (to 3” long and 3/4” wide) have a single primary mid-vein. Mildly fragrant yellow flowers (each to 3/4” across) with 5 rounded petals and numerous long center stamens bloom in clusters at the stem ends from early to mid-summer (June-July). Flowers give way to globular to oval seeded capsules.
This plant can be distinguished from other species of St. John’s wort by the absence of black dots on the flower petals and leaf undersides.
Genus name comes from the Greek words hyper meaning "above" and eikon meaning "picture" in reference to the practice of hanging flowers from this genus above images, pictures or windows.
Specific epithet from Latin means having spherical fruits.
Problems
Watch for rust. Powdery mildew may occur.
Uses
Borders, rock gardens, native plant gardens.