The California pepper tree (Schinus molle) is a wild evergreen tree that grows between 25 to 40 feet tall. In areas such as Australia and South Africa, the California pepper tree and the related Brazilian pepper tree are invasive and have taken over large swathes of land. In other parts of the world, particularly in the Americas, it is cultivated both for ornamental purposes and for spices.
Texas Root Rot
The pepper tree is one of several trees and plants that are susceptible to a condition known both as Texas Root Rot and Cotton Root Rot. This is a fungal disease that occurs throughout the southwestern United States that infects the roots of the tree, rendering it unable to get enough water into its system to survive. This leads the majority of trees that are infected with Texas Root Rot to die in the summer months. Symptoms include dead or dying leaves on the trees and (under close inspection) fungal webs on the surface of the root.
Texas Root Rot can survive for decades in infected soil, making diagnosis and treatment extremely difficult. Treatments that increase the acidity of the soil can help stop growth of the fungus.
Armillaria Root Rot
Armillaria Root Rot is also known as oak root fungus disease or shoestring disease and attacks broadleaf trees like the California pepper tree from the bottom up, frequently causing the roots and area of the trunk near the ground to die. It does this by infecting the cambial tissues, which are the source of cells used by plants in secondary growth. The first symptoms of Armillaria Root Rot are small, discolored leaves dropping early followed by the death of branches near the top of the tree. The fungus can also cause bunches of mushrooms to form along the base of the tree.
As with Texas Root Rot, Armillaria Root Rot can survive in soil for years or even decades. If a section of a tree becomes infected, it may be impossible to save. The best plan is to plant root rot resistant plants and trees along with air drying the soil extensively before replanting.
Artist's Conk is a fungal infection that attacks California pepper trees through wounds and causes white rot of sapwood and heartwood and in some cases can kill the sapwood entirely. It forms semicircular conks that extend up to 30 inches from the tree and that can be up to 8 inches thick. The bottom half of Artist's Conk is white but turns brown when scratched. This leads to its name, as some nature artists can create artwork through etching on the conk.