Q.Butternut trees?
I’m looking at planting a butternut tree/white walnut in my backyard… I discovered them because of their beautiful foliage. I do have a few questions about their toxicity and if it applies to animals (dogs in particular) and yield of nuts. Also I have heard that walnut trees can be a hassle to maintain but I’m not sure how reliable to source is, any guidance/ opinions would be appreciated!

Certified GKH Gardening Expert
Walnuts can be quite aggressive in many climates. They will grow on their own but they will become quite large quite fast.
The toxicity applies to the soil, mostly. Although the nut's flesh can be mildly irritating, it won't cause any harm to animals or humans. This toxin affects other plants in the area. It will have a large impact on tomatoes, potatoes, and anything else solanacious, as well as many other plant species.
This article will help: https://www.gardeningknowhow.com/edible/nut-trees/walnut/growing-butternut-trees.htm