The Mexican bird of paradise (Caesalpinia mexicana) is a flowering shrub native to Mexico and parts of the southwestern United States. This large, sprawling shrub can grow up to 12 feet tall and wide, making it well-suited for use as an accent or specimen plant in warm climates. The Mexican bird of paradise grows at a moderate rate and has naturalized in parts of the southern and western United States. Its bright yellow flowers make it an eye-catching addition to gardens, but some gardeners hesitate to plant Mexican bird of paradise due to concerns that it may spread aggressively. This article will examine the spreading and invasive potential of this plant to help homeowners decide if it is suitable for their landscape.
Does Mexican Bird of Paradise Spread Aggressively?
Mexican bird of paradise has the potential to spread via both seed dispersal and underground rhizomes. However, most cultivars grown ornamentally have been bred to be sterile and produce little to no viable seed. While less common, spreading via underground rhizomes is possible with this plant. Here is a quick overview of its spreading tendencies:
Seed Dispersal
– Wild types produce long seed pods with viable seeds that are dispersed by birds, small mammals, and gravity. This allows the plant to readily colonize new areas.
– Most ornamental cultivars do not set seed and have very low fertility rates. They are unlikely to colonize by seed dispersal.
Underground Rhizomes
– Mexican bird of paradise can spread slowly outward via underground rhizomes. It does not spread aggressively this way.
– Spread rate is gradual, typically just a few feet per year.
So in summary, this plant does have the ability to spread but is generally not aggressive or invasive when grown as an ornamental. Sterile cultivars that do not set seed are recommended for landscape use.
In Which Regions Does Mexican Bird of Paradise Spread?
Mexican bird of paradise is hardy in USDA zones 8-11 and has become naturalized or weedy in certain parts of the southern United States. Here are the key areas where it has shown weedy tendencies:
Southern California
This plant has invaded canyon bottoms and stream sides in parts of southern California. It spreads along waterways and displaces native species in riparian areas.
Southwestern States
Mexican bird of paradise has been reported as invasive in desert riparian areas of Arizona, New Mexico, and Texas. It also grows wild in rocky slopes, arroyos, and dry streambeds.
Florida and Gulf Coast
This species has become naturalized along roadsides and in disturbed sites in Florida. It also grows wild in coastal areas along the Gulf of Mexico.
So in general, Mexican bird of paradise demonstrates weedy behavior mostly in the southern states and hot climates within its hardiness range. It has not proven invasive in colder areas.
Does Mexican Bird of Paradise Spread If Contained or Managed?
When grown as an ornamental, Mexican bird of paradise only spreads minimally if properly contained and managed. Here are some tips for keeping it under control:
Select Sterile Cultivars
Choosing cultivars labeled as sterile, seedless, or non-invasive can prevent unwanted seedlings. Some recommended varieties include ‘Red Bird,’ ‘Moonlight,’ and ‘Staircase.’
Use as Accent Plant
Rather than planting as a hedge or landscape border, use Mexican bird of paradise as a specimen or accent plant. This prevents the long, spreading root system from invading other garden areas.
Prune Regularly
Pruning back leggy stems and wayward branches encourages fullness over spread. Prune annually right after flowering.
Manage Suckers
Remove any underground suckers promptly to prevent the shrub from expanding outwards. Limit root competition from nearby plants.
Grow in Containers
Planting in pots or planter boxes effectively contains the root system and prevents any spread. Overwinter containers indoors in cold climates.
So with proper selection, planting, and maintenance, Mexican bird of paradise can be grown as an ornamental without issue. It only demonstrates aggressive spread when allowed to naturalize outside of cultivation.
Should Gardeners Be Concerned About Mexican Bird of Paradise Becoming Invasive?
For most home gardeners, there is minimal risk of Mexican bird of paradise becoming excessively invasive. Here are some key points:
Not Aggressive When Cultivated
This tropical shrub has only exhibited weedy tendencies where it has naturalized or escaped cultivation. When selected, sited, and maintained properly, it behaves well in ornamental gardens.
Avoid Naturalizing
Homeowners should not allow Mexican bird of paradise to grow wild in areas beyond the garden, such as natural desert or coastal habitats. Do not plant where suckers could spread unchecked.
Monitor Spread
While not quick to spread, rhizomes may expand slowly outward over time. Monitor for suckers and remove promptly to keep growth contained.
May Require More Maintenance
Gardeners in warmer climates may need to prune, dig out suckers, and monitor for spread more than other ornamental shrubs. But this maintenance can easily keep the plant in check.
Right Plant, Right Place
Avoid planting Mexican bird of paradise where it could impact native plants or sensitive riparian areas if it did spread. Select the right site in the landscape.
So for the majority of garden settings, Mexican bird of paradise should not raise serious invasive concerns if properly managed by the homeowner. Monitor spread, prune often, and remove unwanted suckers to keep this beautiful plant in bounds.
Conclusion
Mexican bird of paradise is a showy ornamental plant suited to warm climates. While it does have the capacity to spread both by seed and underground rhizomes, aggressive spreading is generally not an issue when properly selected sterilized cultivars are grown in garden settings. Its bright flowers make it an excellent accent plant for the landscape. Homeowners who monitor for suckers, prune regularly, and prevent any unwanted spread into natural areas should be able to grow Mexican bird of paradise successfully as a low-maintenance shrub. With simple cultural care, its minimal spreading tendencies can be easily kept in check.
