Flower profile
Rattail
Stachytarpheta cayennensis
Rattail (Stachytarpheta cayennensis) is a shrub in the Verbenaceae family, blooming mostly March–December across the U.S.
Rattail is a flowering plant. In Hawaii it's most often seen in bloom in March–December.
*iNaturalist research-grade observations, as of October 17, 2026. Our state lists also include states where people grow it in gardens, so they can outnumber USDA's wild-plant records.
On our lists for: Hawaii
Quick look
Stachytarpheta cayennensis is a species of flowering plant in the verbena family known by many English language common names, including blue snakeweed, Cayenne snakeweed, dark-blue snakeweed, bluetop, nettle-leaf porterweed, rattail, rough-leaf false vervain, blue rat's tail, Brazilian tea, Cayenne vervain, false verbena, joee, nettleleaf velvetberry, and Cayenne porterweed.
- It belongs to the Verbenaceae family. iNaturalist
- USDA PLANTS describes it as a shrub with a perennial life cycle. USDA PLANTS
- In Hawaii, most iNaturalist sightings of it in flower come in March–December. iNaturalist
- iNaturalist has 1,597 research-grade sightings of it in Hawaii, ranking #22 among the 118 flowers on our Hawaii list. iNaturalist
When does it bloom?
In Hawaii, most flowering sightings come in March–December.
Conservation status
- Federal (U.S. ESA)
- Not listed No U.S. Endangered Species Act listing in the USFWS ECOS database. USFWS ECOS
- NatureServe global
- GNR Not yet ranked worldwide. NatureServe
- Hawaii
- Not listed Not on Hawaii threatened and endangered plants (HAR 13-107; the state list follows the federal list), DLNR Division of Forestry and Wildlife. NatureServe has no Hawaii rank for it. HAR 13-107
- Rare elsewhere
- No other U.S. state ranks it S1, S2, SH or SX.
Checked October 17, 2026. Rankings and lists can change, so follow the links for the latest.
Can you eat it?
None of the sources we checked (NC State Extension (no page for this plant), USDA PLANTS) say whether it's edible or poisonous for people.
It isn't on the ASPCA plant list.
🌿 Never eat a wild plant unless you're certain of its ID; this isn't medical advice. Worried about a person? Call Poison Control at 1-800-222-1222. Worried about a pet? Call your vet.
Where does it grow?
USDA PLANTS has no state-by-state distribution for this name, so we can't map it yet.
Names, range and relatives
Native status by region (USDA PLANTS): Pacific Basin (excluding Hawaii): Introduced; Puerto Rico: Native; U.S. Virgin Islands: Native.
Other scientific names (synonyms in USDA PLANTS): Stachytarpheta dichotoma, Valerianoides cayennensis.
County records: USDA PLANTS lists it in 7 counties across 2 states; the most are in Palau (4), U.S. Minor Outlying Islands (3).
More from the Verbenaceae family (14 on Bloomipedia; most observed first): Dakota mock vervain, Blue vervain, White vervain, Hoary vervain, Texas vervain, Lantana, Brazilian vervain, Bigbract verbena.
More Hawaii flowers
Sources
- USDA, NRCS. PLANTS Database, profile STCA8.
- iNaturalist, Stachytarpheta cayennensis: taxonomy, research-grade observation counts and “Flowering” annotations, retrieved October 17, 2026.
- Wikipedia, Stachytarpheta cayennensis (lead quoted under CC BY-SA 4.0).
- Hawaii: Hawaii threatened and endangered plants (HAR 13-107; the state list follows the federal list), DLNR Division of Forestry and Wildlife.
- Hawaii: Hawaii noxious weed list (HAR 4-68).
- USFWS, ECOS species database (ESA listing check), October 17, 2026.
- NatureServe Explorer, Stachytarpheta cayennensis (global and state ranks).
- Edibility and toxicity: no source found (marked "not well documented").
- Photo: nmoorhatch via iNaturalist · CC BY 4.0 · resized.