Erythrostemon mexicanus aka Caesalpinia Mexicana

Erythrostemon mexicanus is an evergreen shrub or small tree. Its common names include Mexican bird of paradise and Mexican holdback. It belongs to the pea family, Fabaceae. Its native range runs from southern Texas into Mexico. There it grows in scrub and dry tropical forests. An older scientific name is Caesalpinia mexicana.

In gardens, it reaches 15–25 feet [4.6–7.6 metres] tall. Its usual spread is 12–18 feet [3.7–5.5 metres]. The crown forms a rounded shape with fine-textured foliage. Lower branches may droop to the ground when space allows. Pruning the lower branches can form a short, single trunk. Brown stems bear small thorns that are easy to miss. The green leaves are bipinnately compound, with oval, smooth-edged leaflets. The foliage stays green without a fall color change. It also gives the plant interest through winter.

Bright yellow flowers grow in clusters at the branch tips. They form on new growth from spring through fall. The display can last for several months across the crown. Flowers attract hummingbirds and other pollinators. The fruit consists of slightly curled, hard, brown pods. These measure 0.25–0.5 feet [0.08–0.15 metres] long. They draw less attention than the flowers. Seeds may sprout near the parent plant. The Florida account reports no apparent spread into other landscapes.

Full sun gives the best bloom, though partial shade also suits it. It needs soil that drains well and tolerates sandy ground. It accepts acidic to slightly alkaline soil. It withstands heat and drought, plus moderate soil salt levels. The listed hardiness range is USDA zones 9–11. Growth estimates vary within the Florida source, from moderate to fast. Care needs are low, and roots seldom cause trouble. Pests do not usually harm its health over time.

This plant serves as a specimen or shrub-border plant. It also suits containers, patio edges, and parking lot islands. Its rounded crown needs room to reach its full width. Fallen flowers, leaflets, and pods can leave litter below. The seeds and pods are toxic when eaten. Eating the pods can cause stomach and gut distress. These parts should not be treated as food. The Florida source does not class the plant as invasive.