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Hydrocharitaceae family

Johnson's Seagrass Halophila johnsonii

Native
Also known as: Species code: Hj

Johnson's Seagrass is a perennial wildflower native to the lower 48 states.

More about this plant

Johnson's seagrass is a small, asexual seagrass in the family Hydrocharitaceae. It has been called Halophila johnsonii, but is now considered to be a clone of the widespread species Halophila ovalis. As of March 2024, Plants of the World Online treats Halophila johnsonii as a synonym of Halophila ovalis subsp. ovalis. Johnson's seagrass occurs only on the southeastern coast of Florida, in lagoons along roughly 200 km of the Florida coastline between Sebastian Inlet and the northern part of Biscayne Bay, where it grows in small patches of a few centimeters to a few meters in diameter at depths ranging from the intertidal zone down to 3 meters. It was the first marine plant listed on the United States endangered species list, though it was removed from the listing in April 2022. Wikipedia →

Growing & care

USDA PLANTS · TRY
Conditions
Sources · Conditions
Cold hardiness (derived) — Hardiness
Hardiness
≥ zone 11 derived from its U.S. range
Size & form
Sources · Size & form
USDA PLANTS — Lifespan
Lifespan
Perennial
In the garden
Herb layer — Sits in the herb of a layered food forest or polyculture.Open guide →
Rain garden / bioswale — Rated OBL on the wetland list — tolerates wet feet, so it suits the soggy zone of a rain garden or bioswale that catches and filters runoff.Open guide →
derived roles
Species characteristics from USDA PLANTS (public domain) + TRY (CC BY) — general guidance, not a guarantee for your exact site. Deer "browsing" is documented palatability, not a deer-proof claim.
Sources for this entry (10) Open & cited
[01] Scientific name & family — USDA PLANTS (DwCA, Zenodo 17903503)
[02] Growth habit & duration — USDA PLANTS (DwCA, Zenodo 17903503)
[03] Native status & distribution — USDA PLANTS (DwCA, Zenodo 17903503)
[04] Common name — USDA PLANTS (via GBIF)
[05] Invasive / introduced status — USDA PLANTS (DwCA, Zenodo 17903503) — native status
[06] Wetland indicator — USACE National Wetland Plant List (2022)
[08] Description — Wikipedia (CC BY-SA)
[09] Cold hardiness (derived) — Derived from U.S. range × USDA PHZM zones
[10] Other common names — Wikidata (CC0)
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