I believe prickly ash is the same as Sechuan peppercorns. The seed coat is used as a spice in some Chinese and other east Asian cooking. It has a pleasantly "cold" burning hotness. From what I've read, there are several species in the genus, so the American species is not necessarily the same as is grown in China, but the culinary properties and uses are the same.
I suppose it's a terrible invasive sometimes, but actually I'd love to get some seed for a certain
project.