Verticillium wilt is a systemic fungus disease like oak wilt and Dutch elms disease, that grows inside the trees vascular system. However, it is not as aggressive of a pathogen and is less serious than some other vascular wilt diseases. Infected trees may survive many years after infection. Increasing the health of the infected plant will sometimes allow the plant to seal the diseased areas beneath a layer of thick sapwood. Verticillium attacks a wide range of woody plants and is common among plantings of ornamental trees and shrubs. Most commonly, the disease is found on maple and ash trees in the landscape.