The Italian cypress is unique among the cypress trees for its towering and slender appearance. Aside from the landscaping appeal, the Italian cypress is a desirable tree because it is unaffected by most tree diseases. Being relatively disease-free makes the Italian cypress easier to care for than many other plant options. However, if disease does become a problem, recognizing the symptoms and taking action quickly can save the tree from further stress or damage.
The Italian Cypress belongs to the cypress family, making it a conifer. Its scientific name is Cupressus sempervirens. The tree is popular for its tall, slender shape which makes it an ideal fence or hedge row tree. With a height or 40 feet or more, they can be planted as close together as 3 feet. Often the height makes them appear like tall, green telephone poles when planted around smaller buildings like single story residences.
Italian cypress trees are relatively disease-free. Phytophthora root rot and cypress canker, sometimes called twig blight are the two diseases that most often affect Italian cypress. Both are fungus diseases. In the case of root rot, there are four types of spores that can cause the disease and it requires the presence of water to germinate the spores. Cypress canker is also caused by spores and emanates during later winter and early spring when there is rainy weather.
Cypress canker infects the bark and cambium of the tree. Infected sections become pale green then yellow followed by death. The disease spreads to new tissue until the entire tree has been killed. Root rot begins in the fine roots, turning them brown. As it moves toward the main roots and up the stem, the tree can be girdled. As the phloem and xylem are affected by the fungus, the leaves are deprived of water and the tree of food. Leaves roll downward and wilt. In larger trees, symptoms can be present for a year before death occurs.
The limb infected with cypress canker cannot be saved. The best you can hope for is to save the tree. The diseased limb should be pruned away and either burned or buried to prevent spores from escaping from it. If the tree becomes seriously infected, it will have to be removed. No new cypress trees should be planted in the area for several years.
Root Rot Treatment
If the tree has shown declining health, root samples should be analyzed to determine if root rot is the cause during late winter. If root rot is found, apply a fungicide soil drench to limit the damage cit can cause in early spring, midsummer and in the fall. If no root rot was discovered, monitor the soil moisture levels to prevent root rot.