Coppery St. John's Wort

Hypericum denticulatum Walt.

Hypericum denticulatum
Robert E. Zaremba

Dicotyledoneae (Dicots)
State Protection
Listed as Endangered by New York State: in imminent danger of extirpation in New York. For animals, taking, importation, transportation, or possession is prohibited, except under license or permit. For plants, removal or damage without the consent of the landowner is prohibited.
Federal Protection
Not Listed
State Conservation Status Rank
Critically Imperiled in New York - Especially vulnerable to disappearing from New York due to extreme rarity or other factors; typically 5 or fewer populations or locations in New York, very few individuals, very restricted range, very few remaining acres (or miles of stream), and/or very steep declines.
Global Conservation Status Rank
Secure globally - Common in the world; widespread and abundant (but may be rare in some parts of its range).


Did you know?

The only population in New York has not been seen in many years but it grows in a habitat that changes from year to year, so it may still be in the seed bank waiting to reappear when conditions are right.

State Ranking Justification

There is one existing population and no other historical occurrences.

Short-term Trends

Several thousand plants were seen in the late 1980s, but they were not seen again until 10 years later when thousands were seen again. No plants have been seen again since 1996 but they may be waiting for favorable pondshore conditions to reappear.

Long-term Trends

There has only ever been one population in New York which was discovered in 1923 and last seen in 1996. The population will probably continue to fluctuate dramatically in the foreseeable future as long as the pondshore remains protected.

Conservation and Management


There are no direct threats to the population.

Conservation Strategies and Management Practices

The pondshores need to be protected from direct disturbance by ATVs and excessive trampling. Exotic invasive species must be prevented from colonizing the shores and any existing populations eliminated at occupied ponds. A natural buffer of at least 200 feet should be established around the ponds to prevent excessive runoff and pollution events.

Research Needs

Research is needed into the status of the seed bank to determine how long seeds can remain viable at the site.



The plants occur on the exposed shore of a coastal plain pond. The pond is set within a pitch pine-dominated pine barrens. The upper pond margin is a sand substrate.

Associated Ecological Communities

  • Coastal plain pond shore (guide)
    The gently sloping shore of a coastal plain pond with seasonally and annually fluctuating water levels. Plants growing on the pond shore vary with water levels. In dry years when water levels are low there is often a dense growth of annual sedges, grasses, and herbs. Submerged and floating-leaved aquatic plants, such as fragrant waterlily and pondweeds, may become "stranded" on the exposed shore. In wet years when the water level is high only a few emergents and floating-leaved aquatics may be noticeable. T

Associated Species

  • Coreopsis rosea (pink coreopsis, pink tickseed)
  • Gratiola aurea (golden hedge-hyssop)
  • Lobelia nuttallii (Nuttall's lobelia)
  • Pinus rigida (pitch pine)
  • Rhexia virginica (Virginia meadow-beauty)


New York State Distribution

There is only one occurrence known from Suffolk county on Long Island. There is one historical record which may be the same occurrence.

Global Distribution

This is primarily a species of the Atlantic coastal plain from Long Island to South Carolina with some inland populations in North Carolina, Tennessee, Georgia, and Alabama. It is most rare in the northeastern part of its range except for New Jersey.

Identification Comments

General Description

This is a perennial wildflower with a single stem that grows 2-7 dm tall. The leaves are elliptic to almost round and 8-20 mm long. They are appressed to the stem so the undersides show and are as long as or shorter than the internodes. Each opposite pair of leaves faces 90 degrees away from the pair above and below it (decussate). The branched inflorescence has flowers with coppery-yellow asymmetrical petals that have a tiny tooth on one side. There are 50-80 yellow stamens surrounding the ovoid fruit which has 3 distinct styles on the top.

Best Life Stage for Proper Identification

The best time to identify this plant is when it is in flower although the appressed leaves could be seen earlier.

Similar Species

Hypericum denticulatum may look similar to other low herbaceous Hypericum species but it is the only one with 50-80 stamens and styles that are 2-4 mm long. The other species have very short styles and up to 22 stamens. Without flowers Hypericum mutilum looks very similar to this species but the leaves are not appressed to the stem.

Best Time to See

The plants are in flower in July and early August when they begin to fruit. The fruits last through October.

  • Flowering
  • Fruiting

The time of year you would expect to find Coppery St. John's Wort flowering and fruiting in New York.

Coppery St. John's Wort Images


Coppery St. John's Wort
Hypericum denticulatum Walt.

  • Kingdom Plantae
    • Phylum Anthophyta
      • Class Dicotyledoneae (Dicots)
        • Order Malpighiales
          • Family Hypericaceae


  • Hypericum virgatum Lam.

Additional Resources

Best Identification Reference

Gleason, Henry A. and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York. 910 pp.

Other References

Clemants, Steven and Carol Gracie. 2006. Wildflowers in the Field and Forest. A Field Guide to the Northeastern United States. Oxford University Press, New York, NY. 445 pp.

Crow, Garrett E. and C. Barre Hellquist. 2000. Aquatic and Wetland Plants of Northeastern North America: A revised and enlarged edition of Norman C. Fassett's a Manual of Aquatic Plants. Volume One: Pteridophytes, Gymnosperms, and Angiosperms: Dicotyledons. The University of Wisconsin Press. Madison, Wisconsin. 536 Pages.

Fernald, M.L. 1950. Gray's manual of botany. 8th edition. D. Van Nostrand, New York. 1632 pp.

Holmgren, Noel. 1998. The Illustrated Companion to Gleason and Cronquist's Manual. Illustrations of the Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York.

Mitchell, Richard S. and Gordon C. Tucker. 1997. Revised Checklist of New York State Plants. Contributions to a Flora of New York State. Checklist IV. Bulletin No. 490. New York State Museum. Albany, NY. 400 pp.

New York Natural Heritage Program. 2010. Biotics database. New York Natural Heritage Program. New York State Department of Environmental Conservation. Albany, NY.

New York Natural Heritage Program. 2024. New York Natural Heritage Program Databases. Albany, NY.

Weldy, T. and D. Werier. 2010. New York flora atlas. [S.M. Landry, K.N. Campbell, and L.D. Mabe (original application development), Florida Center for Community Design and Research University of South Florida]. New York Flora Association, Albany, New York


About This Guide

This guide was authored by: Stephen M. Young

Information for this guide was last updated on: September 6, 2012

Please cite this page as:
New York Natural Heritage Program. 2024. Online Conservation Guide for Hypericum denticulatum. Available from: Accessed May 26, 2024.