The most striking difference lies in their overall form and stature. Strelitzia reginae, the Bird of Paradise, is a clump-forming perennial herb. It lacks a true woody trunk and typically grows to a modest height of 1 to 1.5 meters (3-5 ft). Its growth is acaulescent, meaning the leaf stalks (petioles) arise directly from the underground rhizome, giving it a stemless appearance. In contrast, Strelitzia nicolai, the White or Giant Bird of Paradise, is a massive, tree-like perennial. It develops a distinct, woody pseudo-stem formed from the bases of old leaf sheaths, which can reach impressive heights of 6 to 10 meters (20-30 ft) or more, resembling a banana plant or a traveler's palm in its habit.
The foliage of these two species is distinctly different in size, color, and arrangement. Strelitzia reginae possesses long, slender, lance-shaped leaves that are bluish-green to grey-green in color. The leaves are smaller, typically 25-70 cm long and 10-30 cm wide, with a waxy coating and a leathery texture. They are arranged in a fan-like formation close to the ground. Conversely, Strelitzia nicolai has enormous, banana-like leaves that are deep green and much broader. These leaves can be 1-2 meters long and 50-80 cm wide. They are arranged distichously (in two vertical rows/ranks) on the top of the tall pseudo-stem, creating a large, flat fan. The petioles of S. nicolai are significantly longer, often exceeding 2 meters.
While both produce the characteristic "bird-like" flowers, their inflorescences differ in color, size, and presentation. Strelitzia reginae produces its iconic flower on a long, horizontal scape (flower stalk). The flower consists of three upright orange sepals and three Modifed blue petals, with two fused together to form a nectary and the third acting as a landing platform. The entire inflorescence emerges from a hard, beak-like green bract (spathe). Strelitzia nicolai has a much larger inflorescence. Its flowers are predominantly white with a dark blue-purple "tongue" (the fused petals forming the nectary) and are held within a large, dark blue to nearly black bract. The flower structure is similar but on a grander scale, and the inflorescences are produced at the top of the plant amongst the leaves.
Both species thrive in full sun to partial shade and require well-draining soil. However, their tolerance to environmental conditions varies. Strelitzia reginae is more tolerant of cooler temperatures and can survive brief periods of cold down to approximately -4°C (25°F), especially if protected. It is also more drought-tolerant once established. Strelitzia nicolai is far more sensitive to cold and is severely damaged or killed by frost. It requires a truly frost-free, subtropical or tropical climate to thrive outdoors and demands consistently moist soil, being less tolerant of prolonged drought due to its large, evaporative leaf surface area.
