Not only do mesquites (Prosopis spp.) bloom, but the flowers furnish abundant nectar to honeybees for mesquite honey. Numerous species of mesquite trees are native to North and South America, Africa and Asia. (see Reference 1) They are in the bean family. Flowers are fragrant, fuzzy-looking yellow catkins made up of hundreds of small flowers and are pollinated primarily by bees. Trees are deciduous and make summer shade trees. Mesquites grow in U.S. Department of Agriculture plant hardiness zones 6 through 10, with variations depending on the species.
Three species of mesquite inhabit the American Southwest. Honey mesquite (Prosopis glandulosa) is hardy in USDA zones 6 through 9, growing 25 to 35 feet tall and as wide. Yellow flowers appear primarily in spring but also into summer. It can have multiple trunks for interesting effects. Velvet mesquite (Prosopis velutina) grows to 50 feet tall and wide in USDA zones 9 through 11 and has leaflets that are covered in velvety fine hairs. Cream-colored 2 to 3 inch flowers appear in spring. Screwbean mesquite (Prosopis pubescens) grows in USDA zones 7 through 9 to about 30 feet tall and 35 feet wide. Bright yellow spring flowers give rise to unique seed pods that are tightly wound in a corkscrew shape.
South American Mesquites
Argentine mesquite (Prosopis alba) has lacy pinnate leaves on trees with a height and spread of 20 to 50 feet, and can remain semi-evergreen at elevations below 2,500 feet in USDA zones 9 through 10. Greenish-yellow catkins in spring tend to blend in with the foliage. Chilean mesquite (Prosopis chilensis) has blue-green leaves on branches with spiny stems, with spines up to 2 inches long. Flowers are 1 to 3 inches long and light yellow. Trees can grow to 50 feet tall with an even wider canopy in USDA zones 9 through 11.
Native and non-native mesquite trees grow near each other in urban settings, and the flowers cross-pollinate easily. Trees with hybrid characteristics grow from the resulting seeds, and are usually crosses between Chilean mesquite, Argentine mesquite and velvet mesquite. Hybrids are vigorous, fast-growing plants with growth habits, leaves and flowers midway between parent species. They are often sold as South American hybrids. Hybrids that have the lacy leaves of South American mesquites but are thornless are often preferred by homeowners. Selected trees are propagated through cuttings, air layering or grafts.
In all mesquite species, flowers give way to pods of different sizes and colors depending on the species. Each catkin gives rise to only a few pods, although nearly all the hundred or so flowers it contains get pollinated. Most flowers abort, conserving the available resources for a pod crop that won't deplete the tree. When honey mesquite near Vernon, Texas was sampled for pod production in 1993 and 1995, pod number ranged from 100 to 1,500 per tree on 8- to 12-feet-tall trees. Pods of native mesquites have the seeds surrounded by a dry sweet pulp. Pods are used throughout the mesquite's range as food by native peoples and wildlife.
- Texas A&M University: Texas Natural Resources Server: Mesquite Ecology
- University of Florida Horticulture Fact Sheet: Prosopis Glandulosa
- Arizona State University: Prosopis Velutina
- Texas A&M University Horticulture: Screwbean, Screwbean Mesquite, Tornillo, Screwpod Mesquite, Twisted Bean, Fremont Screwbean
- Arizona State University: Prosopis Alba
- Arizona State University: Prosopis Chilensis
- University of Arizona Desert Legume Program: Aridus: Mesquite Trees for the Urban Landscape