What could cause my mesquite tree to have yellowing, but apparently otherwise healthy, leaves?
My neighborhood has numerous mesquite trees, but mine is the only one with yellowish leaves. New growth is green during the initial growth, but turns yellowish once the leave is mostly formed. The yellow leaves are not dry and do not fall off of the tree. The tree is probably about 30 years old and, besides its color, is typical of those in the neighbor hood. Thanks in advance for any ideas you might have.
Problems with the roots can also cause yellowing of the leaves, otherwise known as chlorosis. Check your planting area: if the mesquite tree’s roots are too confined, this can mean it is unable to take up enough water or nutrients to meet the needs of its canopy, and is therefore shedding leaves. Although yellowing leaves often indicate a lack of water, it can also mean that roots are sitting in water and drowning. This root die-off will result in the tree’s inability to take up enough moisture. Check the soil to make sure it isn't soggy.
Imbalances in the levels of nutrients in the soil can cause yellowing leaves as well. If the mesquite tree is lacking iron, manganese or zinc, leaves can change color. An imbalance in pH can also interfere with the plant’s normal functions, reducing its ability to take up vital nutrients even if they are available in the soil. The optimum pH range for most plants is between 5.5 and 7.0, but mesquites generally tolerate both acidic and alkaline conditions. Apply a balanced fertilizer in mid-winter, such as 10-10-10 or 16-16-16, and see if that fixes the problem. If not, conduct a soil test to determine if your soil has a severe pH imbalance.
Pests and diseases can also cause leaf yellowing. Scale infestations often cause leaves to yellow and drop off the tree. Roundheaded or long horned borers also damage trees, causing foliage to wilt or become discolored and fall off the tree. The best way to combat pests is to provide the mesquite tree with full sunlight, water and nutrients for optimum health.