Habitat:
The root system is deep, wide-spreading, usually with a tap root. A
toxic substance, juglone, is leached from the roots and fallen leaves, inhibiting
the growth of many plants, including young walnut seedlings.
Diseases: Diseases which affect walnuts include a walnut anthracnose fungus (which causes severe defoiliation and canker of stems), wilt, blight and witches' broom. Aphid, walnut caterpillar and walnut scale are the known insect pests of walnut trees.
Distribution: Native to Iowa, this tree has a range from Massachusetts to Minnesota, south to northern Florida and Texas, preferring the fertile, moist, well-drained soils of bottomlands and lower slopes.
