Crossandra infundibuliformis aka Firecracker Flower

Crossandra infundibuliformis is a small shrub that stays green year-round. It belongs to the Acanthaceae family. Its common name is firecracker flower. It is native to Ethiopia and east-central tropical Africa. Its native range also spans India, Sri Lanka, and Bangladesh. Kew places it in tropical regions with a dry season. Gardeners grow it outside in warm places free of frost. In cooler places, they grow it as a houseplant. They also grow it as a summer annual.

Garden plants reach about 1–3 feet [0.3–0.9 metres] tall. RHS gives an upper height of 3.3 feet [1 metre]. Spread reaches about 1–2 feet [0.3–0.6 metres]. The plant grows fast into a dense, upright bush. Its straight green stems are square when cut across. The leaves are simple, with one blade each. They have a lance shape and grow in opposite pairs. Their dark green tops shine, and their edges form waves. Each leaf is about 0.25–0.5 feet [0.08–0.15 metres] long.

The flowers rise above the leaves on upright stems. They grow in dense groups shaped like cones. Each bloom has uneven petals that spread like a fan. The blooms come in salmon pink, apricot, yellow, and orange-red. RHS notes that blooms last from spring through autumn. Bees, butterflies, and dragonflies visit the flowers. The plant forms seed pods once the flowers fade. Rain or high humidity can make the pods burst open. This gives the plant its name, firecracker flower. Heavy rain can also harm the blooms.

Give this plant warmth, high humidity, and bright, filtered light. Deep shade can stop blooms, while direct sun may cause harm. For plants under glass, RHS calls for stronger light from autumn through spring. Use filtered light in summer and compost with no peat. Soil should drain well and hold plenty of organic matter. The plant needs a moderate amount of water. It does not cope with drought. Cold water can harm its roots. Temperatures below 55°F may cause leaf loss. Sources place it in USDA zones 10–11. They give it a UK rating of H1A.

It suits pots, patios, borders, and butterfly gardens. Pinch young shoot tips to help form a fuller plant. Remove spent flowers to help the plant make more blooms. Grow new plants from seeds or stem cuttings. Serious pest and disease problems are rare. Still, aphids, mealybugs, whiteflies, and mites may appear. NC State lists it as non-toxic to cats, dogs, and horses. The supplied sources give no food use. They do not assess its safety for humans.