Firespike: The Hummingbird Magnet That Lights Up Fall Gardens

As autumn approaches, firespike (Odontonema strictum) erupts in brilliant red flower spikes across Florida and the Deep South, drawing hummingbirds and butterflies in droves. This evergreen shrub brings spectacular late-season color and wildlife activity to gardens in zones 8–11.

Plant Profile

Firespike forms upright, mostly unbranched clumps from short root suckers, reaching 4–6+ feet tall. Smooth green stems are woody at the base, succulent toward the tips. Glossy, oblong leaves (4–8 inches long) with wavy margins and pointed tips grow opposite along the stems, creating an attractive foliage display even before bloom.

From late summer through winter (or until frost), the plant produces abundant 9–12-inch racemes of tubular, inch-long florets. Buds are club-shaped; open flowers flare into half-inch, five-petaled stars—a sight easier to admire than describe.

Cultural Preferences

Firespike thrives in fertile, moist soil across a range of light exposures. Partial shade is ideal—plants grow taller with larger leaves. In full sun, they're more compact but leaves may wilt midday, rebounding as light softens. Full shade yields lanky growth. It blooms in all conditions.

In zone 8 and colder, frost kills top growth to the ground. Cut stems back and mulch the crown with pine needles. New succulent shoots emerge in spring, but blooming delays until fall. North of zone 8, grow as an annual or in movable containers. Firespike tolerates heat and drought but not salt. Few pests bother it beyond occasional mealybugs. Deer browse the foliage; butterflies and hummingbirds love the nectar.

Propagation and Naturalization

Propagation is effortless: stick a stem in damp soil, and it roots. Fallen stems root where they touch ground. This ease has allowed firespike to naturalize in Cuba, Puerto Rico, Hispaniola, and peninsular Florida, mostly from abandoned gardens or dumped plant material. Seeds germinate poorly; spread is vegetative.

The Scientific Name Puzzle

Taxonomy remains unsettled. References variously list Odontonema strictum, O. cuspidatum, or O. tubaeforme. GRIN treats O. strictum as a synonym of O. cuspidatum, suggesting a name change. O. callistachyum (pink/purple flowers) and O. nitidum are distinct, but O. cuspidatum and O. tubaeforme appear identical in most photos. Until consensus emerges, "firespike" works perfectly.

At a Glance

Common names: firespike, cardinal guard, scarlet flame
Family: Acanthaceae
Hardiness: USDA Zones 8–11
Origin: Mexico and Panama
Salt tolerance: None