Hypericum prolificum L.

Shrubby St. John's-Wort

Hypericum prolificum plant

Family - Hypericaceae

Stems - Woody, multiple from the base, branching, erect, to 2m tall, with shredding bark.

Hypericum prolificum stemMature stem.

Leaves - Opposite, sessile, oblong to lance-oblong, dark green above, lighter green below, glabrous, decussate, entire, with minute whitish tip, with single prominent midrib, to +3cm long, +/-1cm broad.

Hypericum prolificum leaves

Hypericum prolificum leavesFlowering branch

Inflorescence - Single axillary flowers on new seasons growth. Flowers sessile or on short pedicels to 5mm long.

Flowers - Petals 5, yellow, distinct, to +/-1.5cm long, 7mm broad, glabrous, oblong to narrowly obovate, rounded at apex. Stamens many, (+100), erect. Filaments yellow, 8-9mm long, glabrous. Anthers yellow, .6mm broad. Style 4-5mm long, glabrous. Ovary superior, ovoid, glabrous, pale greenish-yellow, 4mm long, 2mm in diameter, 3-locular. Placentation axile, ovules(seeds) many. Sepals 5, unequal, to 6mm long, +/-3mm broad, glabrous, acute, spreading to slightly recurved.

Hypericum prolificum calyxCalyx.

Hypericum prolificum flowerFlowers

Hypericum prolificum fruitMature fruit.

Flowering - June - September.

Habitat - Rocky open ground, streambanks, bluffs, wooded slopes, low moist ground, also cultivated.

Origin - Native to U.S.

Other info. - This species grows wild throughout the majority of Missouri, excluding the northwest corner of the state. The plant is also becoming more popular in cultivation.
H. prolificum is easy to identify becasue of its pon-pom like flowers, shrubby habit, opposite leaves, and shredding bark.

Photographs taken at Logan Creek, Reynolds County, MO., 7-3-04 (DETenaglia); also at LaBarque Creek Conservation Area, Jefferson County, MO, 7-18-2016 (SRTurner).