Mesquite trees are a hardy desert tree that has adapted over centuries to live in desert landscapes around and in Arizona. The physical characteristics of these trees help to ensure survival which include the bean pods, root systems and foliage. They happen to grow well in high temperatures and full sun, but they do not tolerate the cold during the winter. They are often found within high elevation areas and can adapt to rocky, shallow soils. The U.S. Department of Agriculture and Forest Service has stated that mesquite trees can live for more than two centuries.

The mesquite trees that are in Arizona are able to survive where there will be hardly any type of rain due to their unique root system. The Mesquite tree’s lateral roots that is has can reach out much further than the canopy ever will. Not to mention they happen to have tap roots that go very deep to get water well beyond 150 feet down, however 50 feet down is more typical. So, the mesquite tree will have access to water both at the bottom and top layers of soil.

The leaflets of the mesquite tree are tiny and waxy and they can retain moisture by minimizing the moisture that is lost through transpiration. The mesquite tree is deciduous which means that they give great shade during summer but will drop leaves and allow the sun to shine on it during the winter to keep warm. During times of extreme drought, they will lessen transpiration even more by prematurely dropping their leaves.

Mesquite trees are considered to be of the legume family which means that it is adapted to arid environments. They also have the ability to fertilize themselves and the surrounding plants using a symbiotic relationship with the soil bacteria colonies. The bacteria that will inhabit the roots of the mesquite tree will fix or convert atmospheric nitrogen which makes it available within the soil. It is a mineral that is essential for the germination and growth of plants. Most gardeners will use the same type of process to enrich their soil by actually using cover crops that are nitrogen fixing.

The mesquite trees that are within Arizona are very prolific. The beans from the tree are very durable when encased within their pods. If a seed has been undisturbed then it can be viable up to about 40 years. Animals will play a big part in the scarification of the seeds which is actually need for germination and the dispersal through their fecal matter.

• PROSOPIS PUBESCENS – These are called screwbean mesquites which earned its name from the coiled or spiraled shape of the seed pods.
• PROSOPIS GLANDULOSA – Is called the Texas Mesquite or honey Mesquite. They are normally have a weeping form and is very pretty.
• PROSOPIS VELUTINA – Is called the native mesquite or Arizona mesquite. It is also called the velvet mesquite because of the soft hairs that cover the young. They are shaggy and snarled and are very popular in nurseries and will grow well on golf courses and lawns.

Besides these mesquite trees, there are a lot of other types of mesquite trees that happen to grow within Arizona. There are hybrids of Screwbean, honey and velvet mesquite, which happen mostly where the species happen to overlap. There are other nonnative species which originate from South America. There is the Chilean mesquite and Argentine mesquite as well as other hybrids and varieties. The nonnative species will be suited to the climate that is here just like the ones that are native to Arizona. For instance, the Chilean mesquite isn’t as tolerant of winter temperatures in Arizona.

Despite all of the positive qualities, mesquite trees are actually considered to be an invasive weed. In most countries outside of South and North American where they have been introduced, they are extremely invasive and a big issue especially in Australia.

Mesquite trees are also cursed by the inhabitants within the Arizona desert. Cattlemen especially hate them, but overgrazing by herds over the previous centuries have really made the problem that they complaint about, which is that the competition with the grass. In areas that are overgrazed, the cattle are not only threatening the population of natural grass that have often competed with mesquites for water, but it also helps the trees by eating as well as then dispersing mesquite seeds. All of the efforts that have been made to stop and control the mesquite tree have failed and it has been stated to be ineffective and impractical. Whether it be done by herbicide, physical removal, or fire, the costs and side effects to the environment by trying to control the population and spread has made it an issue without an easy solution.

Many arborists state that whether it is a welcomed thing or unwanted item, the mesquite tree belongs in the desert. They have evolved in the desert and they actually play a main role to the desert ecosystem.

Even though the mesquite tree doesn’t need a lot of maintenance, the ones that are growing around your home could use some extra care whenever there is a very hot summer or during extended droughts. Sun-scorch happens to be is one issue that could hurt a mesquite tree that has been planted within the landscape, however they aren’t as susceptible as a citrus tree. Deep watering every now and again and some occasional fertilization will help to make sure that the mesquite trees are around won’t decline in beauty of health.

During the times when there is plenty of rain, mesquite trees will not need any extra watering. However, when there is a drought, the leaves will become sparse and will allow more sun through the branches. This is caused by the need in cities to keep mesquites thinned out to survive heavy winds and storms, so that it won’t cause damage to structures and homes. If the bark is exposed to too much sun, sun-scorch can happen, especially in direct sunlight. Sun-scorch will cause permanent damage to the sapwood layer under the bark. The dead tissue and cracked bark can cause a secondary infection and infestations like sooty canker and bark beetles.

Sun-scorch can be prevented but it can’t be undone. Reflective paint when placed on vulnerable branches will help a mesquite from being sun damaged. The branches that are affected, need to be removed. The best way to prevent sun scorch is to encourage leaf growth to protect the tree during hot parts of the year by watering and fertilizing. If you give the tree ammonium sulfate once during spring, it helps. Unless it is fed by sprinklers or drippers, water the tree deeply every 2 months from early spring to fall. If monsoons bring plenty of water, then you will not need to deep water.

Mesquite trees that are planted in someone else’s property may not be as strong as the trees in the desert. Most likely they are nursery grown that was planted for use in landscaping and has spent time in a pot. The more time that the tree spends in a pot, the more likely it is to be root bound. Impaired root systems can make a tree struggle to receive what water they need to live, but also makes it prone to falling over because the anchoring isn’t very sturdy. You can try as hard as you want, but it is near impossible to make a wobbly tree anchor into the ground. Whenever you place stronger stakes and wires and putting the tree back in place when it falls, then you are just prolonging the inevitable. The absolute best thing that you can do for a severely unstable tree is to just remove it and then start all over using a healthy tree.

If nothing else, we certainly do hope that this article about mesquite trees within Arizona can help to increase the appreciation for this wonderful native plant as a tree that certainly belongs in the desert that all Arizonan’s call home.

As J. Frank Dobie once stated, “Primroses burn their yellow fires, where grass and roadway meet; feathered and tasseled like a queen, is every old mesquite.”