Inspect the leaves of your plant. Deep green leaves with a high gloss signify a tropical hibiscus. Heart-shaped, dull-colored leaves signify a hardy hibiscus.
Check the flower color of the plant. Hardy hibiscus flowers have red, pink or white flowers, according to the Tropical Hibiscus website. Tropical plants have bright salmon, peach, orange or yellow blooms.
Inspect the shape of the flower. The tropical variety has double flowers, while the hardy hibiscus has large buds in the center of its flowers, averaging about 2 to 4 inches in size.
Consider the current season and where you bought your hibiscus plant. If it's cold outside and you purchased the plant from an outdoor display, you have a hardy plant. The tropical hibiscus needs warm weather or a greenhouse environment to survive.