June 14, 2002

Black Walnut Toxicity

Black walnuts (Juglans nigra) are native to Iowa and found throughout the state. They are prized for their beautiful wood and tasty nuts. However, black walnuts are poor trees for many home landscapes. Not only are the nuts messy, they also create difficult growing conditions for vegetable and flower gardens.


Mulches can be a valuable addition to any landscape. Used in a well managed garden, they can enhance beauty, suppress weeds, and keep moisture near the plants. The big question in mulches is can they harbor disease-causing fungus that can be dangerous to plants? The answer is mixed. It is possible to transfer diseases such as pine wilt, but only when infested mulch is incorporated into the soil, placed against a wounded tree, or isn't composted. Verticillium wilt isn't known to infect trees when infested mulch is used, but may infect vegetable plants when used as a garden mulch.

Wood Cockroach

Wood cockroaches, also known as wood roaches, are common outdoor-dwelling insects native to North America and found throughout Iowa. Their normal habitat is moist woodland areas but they frequently become a household nuisance because they wander into or are carried into houses as "accidental invaders."