A Technical Report from The Bartlett Tree Research Laboratories
Phytophthora root disease is a widespread but often overlooked disease of landscape plants. The name, Phytophthora, is a Greek word literally meaning “plant destroyer.” These organisms grow in the cambium and sapwood causing death of the tissue. Loss of water, nutrient-absorbing capacity, and stored carbohydrate reserves in the root cause a gradual, or sometimes rapid, decline of the above-ground portion of the plant. A list of plants tolerant of poorly drained soils is included in this technical report.
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- I planted six young trees in early March. Despite watering them regularly they have all started to wilt and the leaves are starting to turn yellow.
- I planted an ornamental cherry tree in my front lawn and noticed bleeding around the bottom of the trunk. This season, it bloomed but has a considerable reduction in leaves. Is there a problem?
- Two of my vine maples have root rot and collar lesions. Will Phytophthora spread to the others, and should I remove the dying trees? Is there an effective treatment for the rest?
- My two 25-year-old Horse Chestnut trees started showing leaf discoloration this summer, and now red liquid is oozing from the bark. Is there a cure for this disease, or do the trees need to be removed?
- We planted a tree in the fall, following the grower’s instructions, but several lower branches are browning. Could poor drainage from a wet winter and spring be the issue, and what can we do to help the tree recover?
- Our 13-year-old Rhododendrons have been declining over three years, despite feeding, watering, and treating for bacterial infection. Leaves curl, turn brown at the tips, and appear pale with dark green veins, while undersides show tiny rusty/brown dots. What should I do?