Selective pruning during the first three years may control tree shape. Mesquites grow so fast that the top branches start to droop and the tree may lean to one side. By removing out-of-place branches, the tree may be trained into an upright dome shape with a symmetrical spreading canopy. You can remove up to 20 percent of the canopy without seriously restricting root growth on the tree. And it is often advisable to prune a second time three to four weeks after the first pruning. Excessive pruning, however, will result in flushes of dense, spindly growth, making the tree even more top-heavy.
In some cases, multitrunked mesquites may be used to provide a different and unique appearance. Trees with multibranching trunks are often used in locations where the primary concern is not the shade the tree produces.
In the summer, thornless hybrid mesquites produce an abundance of lacy, fernlike compound leaves. These provide nice, filtered shade under the tree, a welcome treat on a hot summer day. In the winter, the tree becomes semideciduous but still retains a good portion of their leaves. Later in the spring, these old leaves are shed and replaced by new leaves. In the late spring, yellow-green inconspicuous flowers form, which later turn into curled tan seedpods.
There is a bumper crop of seedpods dropping from mesquites right now. New trees may be grown from this seed, but it takes a little doing. If you have a tree, then you may get more trees by watering the area below the canopy and watch for new trees to sprout. Dig up the new tree seedlings and pot them or transplant them to the desired location. Since thornless mesquites will cross with other mesquites, the new trees from the beans may or may not be close to the appearance of the parent tree.
Planting the beans requires that you dig the beans from the pod, scarify or cut the hard seed coat without injuring the tender embryo inside, soaking the seed overnight and planting the seed in potting soil.
If you don't want to try to grow your own trees from beans, there are a number of local nurseries that supply them for a relatively low price. Choose one-gallon size containers as mesquites grow very fast. The less the root system is held back, the faster the tree will grow. Five-gallon trees are often the unsold and repotted one-gallon trees in a larger container.
Mesquites will respond to fertilizer and water with faster growth than if left alone. However, if the tree were growing in the lawn, we would recommend fertilizing the turf and letting the tree get the leftover fertilizer. Additional fertilizer may cause excessive canopy growth resulting in broken branches during high winds.
If you have a corner that doesn't get too much water, then a thornless hybrid mesquite with one or two bird of paradise shrubs makes a spectacular attraction to any landscape. They are the perfect duo for a desert setting.