My California Pepper Trees Are Turning Yellow

The California pepper tree produces dark-green foliage on single or multi-stemmed, gray-colored trunks. Though it has upright branches, its canopy droops in a weeping form that makes the California pepper an ideal shade tree. As a tropical evergreen, the yellowing foliage on a California pepper is a true sign of distress and should be treated promptly to avoid permanent injury to the tree.

Deficiencies and Excesses

Though tolerant, the California pepper tree requires a loamy, well-drained and well-balanced soil environment for best growth. Soils that provide excessive nutrients or are nutrient deficient causes this tree to experience ailments that are reflective of the imbalance. The nutrient deficient California pepper tree develops yellow, necrotic foliage often curls and becomes spotted. The California pepper that has excessive nutrients develops yellow and brown discolorations around the tips of the foliage, or marginal leaf chlorosis. Excessive and deficient nutrient levels cause the California pepper tree to experience growth stunt and dieback.

Nutrient Correction

In order to correct the nutrient deficiencies and excesses in the California pepper tree’s planting area, you must determine the nutrient levels in the soil. Take a soil sample from the planting location and complete a soil test to determine those levels. Purchase a soil test from your local home improvement or nursery location. Dig a hole about 6 to 8 feet deep into the soil near the roots and take a sample from the bottom of the hole. Use the results from the soil test to determine the appropriate adjustments. Talk to your local horticultural or nursery specialist for correction assistance.

Leaf Burn

Nutrient imbalances weaken the California pepper tree, making it susceptible its environment and resulting leaf burn. The weakened California pepper becomes susceptible to sunlight, excessive heat, drought conditions, heavy wind and cold temperatures. The ailment results in yellowing foliage that may turn brown, wilt and then defoliate from the tree in severe conditions. A vigorously growing California pepper tree raised in balanced, well-drained soils is able to defend itself from leaf burn.

Verticillium Wilt

Verticillium wilt is a soil-borne disease that infects the California pepper tree through its root system. Transported by fungal spores, the spores infect the tree’s vascular system which inhibits the tree’s ability to move nutrients and water to its limbs and leaves. The infected California pepper tree’s leaves yellow from the lack of nutrients and eventually turns brown and defoliated from the tree. The branches and stems experience dieback while the entire tree experiences growth stunt and eventual death from the infection. There is no cure for verticillium wilt infections and the infected California pepper tree should remove and destroyed.

References

• University of Arizona Pima County Cooperative Extension: Schinus Molle
• University of California Cooperative Extension: Pepper Tree (California Pepper Tree) -- Schinus Molle
• University of California Cooperative Extension: Leaf Burn or Scorch
• University of California Cooperative Extension: Mineral Deficiencies
• University of California Cooperative Extension: Nutrient and Mineral Excesses
• University of California Cooperative Extension: Verticillium Wilt
• Virginia Cooperative Extension: Why and How to Test Your Soil