// SPECIES PROFILE · PERENNIAL · NATIVE

Roundseed st. john's-wort

Hypericum sphaerocarpum

Roundseed st. john's-wort (Hypericum sphaerocarpum) is a perennial in the — family. Native range includes AR, KS, MO, OK. Hardy in zones 3a–10a. Mature size 6"–2'. Blooms Jun–Aug.

// QUICK FACTS

Family: —
Group: perennial
Native range: Native to 17 U.S. states, including AL, AR, IA, IL, IN, KS…
USDA hardiness: Zones 3a–10a
Mature size: 6"–2'
Sun: —
Water: —
Bloom: Jun–Aug
Wildlife value: Pollinator and wildlife support
Ecological role: native species profile

Roundseed st. john's-wort (Hypericum sphaerocarpum) — *Hypericum sphaerocarpum* — Roundseed st. john's-wort. Photo by Mason Brock (Masebrock) via Wikimedia Commons (Public domain).

Field Notes

[ growing · ecology · siting · care ]

Roundseed st. john's-wort (Hypericum sphaerocarpum) is a perennial in the — family. Native range includes AR, KS, MO, OK. Hardy in zones 3a–10a. Mature size 6"–2'. Blooms Jun–Aug.

Why it's on this list: native species profile. Native-range data from the Lady Bird Johnson Wildflower Center (NPIN), cross-checked against iNaturalist observations. Part of Rooted Revival's regional native plant catalog — true natives for Oklahoma, Arkansas, Missouri and Kansas.

Companion Planting

[ guild · polyculture · cross-layer pairings ]

In the same native range, roundseed st. john's-wort pairs naturally with: American Lotus (Nelumbo lutea), Broadleaf Arrowhead (Sagittaria latifolia), Butterfly Milkweed (Asclepias tuberosa), Cardinal Flower (Lobelia cardinalis).