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Hypericum adpressum Raf. ex W. Bart.
Bog St. John's-wort
Federal Protection: No US federal protection
State Protection: No Georgia state protection
Global Rank: G3
State Rank: S1
Element Locations Tracked in Biotics: Yes
SWAP 2015 Species of Greatest Conservation Need (SGCN): Yes
SWAP 2025 Species of Greatest Conservation Need (SGCN): Yes
2025 SGCN Priority Tier: High Conservation Concern
Element Occurrences (EOs) in Georgia: 5
Habitat Summary for element in Georgia: Swamps
Perennial herb with erect, hairless stems, 16 - 32 inches (40 - 80 cm) tall, forming colonies by underground stems (rhizomes). Stems are thick and spongy when growing in water; unbranched except in the flower cluster. The leaves are 0.6 - 3 inches (1.5 - 8 cm) long and up to 0.4 inch (1 cm) wide, narrowly oblong or lance-shaped, hairless, with strongly inrolled edges, opposite or in whorls of 3 leaves. The flower cluster is held at the top of the stem, with several forking branches and leaves in the lower half. The flowers are about 0.6 inch (1.6 cm) wide, with 5 persistent yellow petals, 5 green sepals with brown midribs, an ovary with 3 styles that are fused and appear to be one style, and many showy stamens. The fruit is an oval, pointed capsule, up to 0.2 inch (4.5 mm) long, with a single, straight, pointed beak (the fused styles) at the tip.
Other non-woody, herbaceous St. John’s-wort species in Georgia’s Coastal Plain have hairy stems (Hypericum setosum) or three separate styles. Hypericum adpressum is also distinguished by its narrow leaves with inrolled margins and the single, persistent beak on the capsule.
Hypericum buckleii (Blue Ridge St. John’s-wort) occurs in rocky crevices on high elevation rock outcrops in Georgia’s Blue Ridge. For more information, see: https://www.georgiabiodiversity.org/portal/profile?group=plants&es_id=21435
Hypericum denticulatum (St. John’s-wort) occurs in bogs, seeps, and moist pine savannas in Georgia’s southeast Coastal Plain. For more information, see: http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=250100871
Hypericum dolabriforme (Glade St. John’s-wort) occurs in limestone glades and woodlands in northwest Georgia. For more information, see: http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=250100863
Hypericum erythreae (Georgia St. John’s-wort) occurs in pitcherplant bogs, wet savannas, and open roadside ditches and powerline rights-of-way through these habitats in Georgia’s Coastal Plain. For more information, see: https://www.georgiabiodiversity.org/portal/profile?group=plants&es_id=17453
Hypericum sphaerocarpum (Barrens St. John’s-wort) occurs in limestone glades and Coosa Valley prairies in northwest Georgia. For more information, see: https://www.illinoiswildflowers.info/prairie/plantx/rf_stjohnwortx.htm
Open, shallow depression ponds, marshes, bogs, and sunny edges of cypress ponds.
Bog St. John’s-wort is a perennial herb that reproduces sexually by seeds as well as vegetatively by the spread of underground rhizomes. No studies of the reproductive biology of Bog St. John’s-wort have been published, but its flowers are likely pollinated by bees that are attracted to its showy flowers and abundant pollen since, like most members of this genus, Bog St. John’s-wort probably does not produce nectar. Bog St. John’s-wort is probably self-incompatible and depends on insect visitors to effect cross-pollination in order to produce fruit.
Surveys are best conducted during flowering (July–August), although its hairless, lance-shaped leaves with inrolled margins distinguish it from other Coastal Plain herbaceous species of St. John’s-wort throughout the growing season.
Georgia, north to Massachusetts, and west to Missouri.
Ditching and draining of ponds, bogs, and marshes; fire suppression; logging and other mechanical clearing in wetlands; conversion of wetlands to agriculture and pine plantations.
| Threat 1 | Threat 2 | Threat 3 | |
|---|---|---|---|
| General Threat | Pollution | Climate change & severe weather | None |
| Specific Threat | None | None | None |
Hypericum adpressum is ranked S1 by the Georgia Department of Natural Resources, indicating that it is critically imperiled in Georgia. Five populations have been documented in Georgia since 1824, but only 2 have been seen in the last 20 years. Only one population occurs on conservation land.
Allow prescribed fire in surrounding savannas and uplands to burn across ponds and bogs. Avoid placing roads and fire breaks around ponds and marshes. Protect wetlands from ditching, draining, and conversion to agricultural and silvicultural activities.
Chafin, L.G. 2007. Field guide to the rare plants of Georgia. State Botanical Garden of Georgia and University of Georgia Press, Athens.
Enser, R.W. 2001. Hypericum adpressum (creeping St. John=s-wort) conservation and research plan. New England Wild Flower Society, Framingham, Massachusetts. https://www.nativeplanttrust.org/documents/69/Hypericumadpressum.pdf
GADNR. 2020. Element occurrence records for Hypericum adpressum. Georgia Department of Natural Resources, Wildlife Resources Division, Social Circle, Georgia.
Godfrey, R.K. and J.W. Wooten. 1981. Aquatic and wetland plants of southeastern United States, Vol. 2, dicotyledons. University of Georgia Press, Athens.
NatureServe. 2019. Hypericum adpressum comprehensive report. NatureServe Explorer. Arlington, Virginia. http://explorer.natureserve.org/servlet/NatureServe?searchName=Hypericum+adpressum
Radford, A.E., H.E. Ahles, and C.R. Bell. 1968. Manual of the vascular flora of the Carolinas. University of North Carolina Press, Chapel Hill.
Robson, N.K.B. 2015. Hypericum adpressum species account. Flora of North America, Vol. 6. Oxford University Press. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=242416675
Sorrie, B.A. 1998. Noteworthy collections: Georgia. Castanea 63: 496-500. https://www.jstor.org/stable/4034002?seq=2#metadata_info_tab_contents
Weakley, A.S. 2015. Flora of the southern and mid-Atlantic States. University of North Carolina Herbarium, University of North Carolina, Chapel Hill. http://www.herbarium.unc.edu/flora.htm
Linda G. Chafin
L. Chafin, Mar. 2007: original account
K. Owers, Feb. 2010: added pictures
G. Krakow, Apr. 2016: updated link to New England Wildflower Society
L. Chafin, Feb 2020: updated original account.
