Not to be confused with the South African native bird of paradise, Mexican bird of paradise (Caesalpinia mexicana) becomes a small, loosely open-branched tree that bears fragrant yellow flowers in summer and fall. If frosts never occur, Mexican bird of paradise grows 15 to 25 feet tall and 12 to 18 feet wide. This member of the bean family grows vigorously in warmth and fertile, moist, well-drained soils but dies back if frost occurs, sprouting back in spring to become a shrub only 6 to 8 feet tall. Grow this evergreen tree outdoors only in U.S. Department of Agriculture Hardiness Zones 9 and warmer.
Wear thick fabric or leather gloves prior to handling branches in the Mexican bird of paradise tree. Tiny, easily hidden, sharp thorns line the leafy branches.
Prune away any dead or damaged/broken branches anytime of year encountered. Make the pruning cut with a hand pruners 1/4 to 1/2 inch above a lower leaf or living branch junction.
Reduce the length of branches to control the size or shape of the tree. Plan on conducting this annual pruning of Mexican bird of paradise in early spring just before or as newly growth emerges from twig tips. Again, make pruning cuts 1/4 to 1/2 inch above a leaf or branch junction regardless of how much branch you aim to remove. Trim branches evenly across the entire plant.
Deadhead old flower clusters from the branch tips in summer and fall to encourage additional flower production. Brown seed pods form after flowers wane, so if you don’t wish to look at these pods, cut off old flowers across the summer. Otherwise these pods ripen, split open and release seeds. According to the University of Florida, these seeds do not germinate and grow rampantly; Mexican bird of paradise isn’t regarded as a weedy or invasive plant.
Trim branch tips lightly as needed in summer and fall to balance out the shape and size of the tree. Any branches that droop to pose a safety hazard over walkways, roads or rub into a building facade need trimming.
If frosts kill the Mexican bird of paradise back to the ground in USDA Zone 9, hold off pruning away all dead branches until early spring. It rejuvenates even from stumps cut back to 6 inches. The plant rapidly re-sprouts in the warmth of spring and summer to create a large shrub.
If any branches are larger than 3/4 inch in diameter, use a loppers to make pruning cuts.
Do not prune Mexican bird of paradise in the fall and winter months since little or no regrowth occurs. If any new stems or leaves emerge, they may be nipped by winter frosts or cool weather. Hold off pruning until early spring unless the branches warrant immediate removal, like those broken or dangling as a hazard over a sidewalk.