Roundseed St. John's-wort

Hypericum sphaerocarpum

Other common name(s):

Family:

Hypericaceae (St. John's wort Family)

Plant Ecoregion Distribution Map

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Texas Blackland Prairies
Northern Blackland Prairie

Plant Characteristics

Growth Form

Herbaceous, Shrub

Height

1
to
2
ft.

Spread

1
to
2
ft.

Leaf Retention

Deciduous

Lifespan

Perennial

Habitat and Care Requirements

Soil Type(s)

Sand, Clay, Gravelly, Rocky, Calcareous, Dry

Light Requirement

Sun, Part Shade

Water Requirement

Low, Medium

Native Habitat

Grassland, Woodland

Bloom and Attraction

Bloom Color

Yellow

Bloom Season

Summer

Seasonal Interest

Pollen, Larval Host

Wildlife Benefit

Beetles, Butterflies, Bees

Maintenance

Works well in borders and rock gardens,. Low maintenance. Drought tolerant. Tolerates a wide variety of soils. Also tolerates wide fluctuations in soil moisture ranging from periods of drought to periods of swampy conditions. Spreads by rhizomes and self-seeding, Native habitat: this species grows in disturbed and calcareous rocky prairie remnants, wooded banks of streams and in sandy soil along roadsides. Rare in the wild in Texas, but can be found in specialty nurseries. Watch for rust. Powdery mildew may occur. Propagation: seed.

Comments

Blooms June-August. Stems often clustered, herbaceous above, woody toward the base. Leaves are narrow oblong to narrow elliptic with a tapered base and pointed to rounded or blunt tip. Flowers: borne in a highly branched and compact inflorescences. The fruit: is a one-chambered capsule,, spherical to egg-shaped,, beaked, containing many seeds. Larval host: Trymon melinus (Gray Hairstreak, Nedra ramosula (Gray Half-Spot).
Previous Scientific Name(s): Hypericum sphaerocarpum var. turgidum, Hypericum turgidum
Material Treatment Method Collection References
Seed No Treatment Let nature handle the stratifying through a dormant seeding, sowing seeds on the surface of a weed-free site in late fall or winter. https://www.prairiemoon.com/hypericum-sphaerocarpum-round-fruited-st-johns-wort

About the Region

Fall Symposium 2025 Logo - Teach for the Future

Salado, the location of our Fall 2025 Symposium, lies at the intersection of two ecoregions: the Edwards Plateau (Limestone Cut Plain) and Blackland Prairie (Northern Blackland Prairie).

The Edwards Plateau area is also called the Hill Country; however, this general term covers a much larger area extending farther north. Spring-fed creeks are found throughout the region; deep limestone canyons, rivers, and lakes (reservoirs) are common. Ashe juniper is perhaps the most common woody species found throughout the region. Additional woody species include various species of oak, with live oak (Quercus fusiformis) being the most common. Sycamores (Platanus occidentalis) and bald cypress (Taxodium distichum) border waterways. This area is well known for its spring wildflower displays, though they may be viewed in spring, late summer, and fall, as well. According to Texas Parks and Wildlife, average annual rainfall in the Edwards Plateau ranges from 15 to 34 inches.

The Blackland Prairie extends from the Red River south to San Antonio, bordered on the west by the Edwards Plateau and the Cross Timbers, and on the east by the Post Oak Savannah. Annual rainfall averages 30 to 40 inches, with higher averages to the east. This region is dominated by prairie species. The most common grass species include little bluestem (Schizachyrium scoparium) and Indian grass (Sorghastrum nutans) in the uplands and switchgrass (Panicum virgatum) in the riparian areas and drainages. Common herbaceous flowering plants include salvias, penstemons, and silphiums. This area has suffered greatly from overgrazing and agricultural use. Few intact areas remain, though many of the plants can be found along county roadsides throughout the region.

Our fall Symposium host chapter, the Tonkawa Chapter, includes both of these ecoregions.

Source: Wildflowers of Texas by Michael Eason