Grow them for nuts or timber, black walnuts are prized, fast growing trees. 

I collect seed only from upstate NY, healthy trees free of nectria canker ( a disease that ruins the timber, but can be genetically selected out).

The Beast A monster of a mother tree. Excellent timber form. Decent sized nuts. Produces enormous crops regularly.

Cracker This tree is a grafted selection planted 70 years ago in an old plantation of walnut cultivars. Unknown name, I call it cracker because the nuts are very large and crack out easily. Easy to hull and good disease resistance