[5] The plant tends to occupy locations near a water source, providing its roots with consistent hydration via groundwater from the saturated soil.

As is typical of the genus, all display the characteristic "lip" petal near the opening of the flower and a "milky" secretion when the plant is broken.

If not planted in or around a water source, L. cardinalis tends to prefer for its roots to stay cool, something achieved when grown in dappled sun or part shade.

[16] As a member of the Lobelia genus, L. cardinalis contains a number of naturally-occurring, toxic alkaloids, including lobelanine and lobeline,[17] thus rendering the species potentially harmful if ingested.

[18] Various negative physical symptoms may manifest upon consuming even small or mid-sized quantities of the plant, including nausea, vomiting, diarrhea, excessive salivation, fatigue/exhaustion, weakness, dilation of pupils, convulsions, and even coma.