To be fair, a lot of Asian ingredients have picked up such weird English translations that they could use a rebrand. Case in point: "Prickly pear ash" is an amazingly unappetizing translation of the spice's proper name, sanshō or sancho.
Part of the problem with the English translations is this ambiguity. Sansho comes from a different species (Zanthoxylum piperitum) of the same genus, native to Japan and Korea. The flavor is different, but reminiscent. I keep both sansho and red Sichuan peppercorns for use in different dishes.
Is that prickly ash? Like a toothache tree with all the sharp spikes on the trunk?
It looks like sancho is the berry produced by the tree. The leaves look similar to our toothache tree or Hercules Club as some call it. I know that the bark here in NAmerica has been used as a local anesthetic for a long time. It produces a tingly, numbing sensation when it becomes wet. I have used the bark to numb gums or throat pain. I never tried the berries.
My tree here died in the last drought. It was a birdshit variety since it was growing along the fence. The seed was dropped by a bird as it rested on the fence and I got a tree as a result! Gotta wait for the next one I guess.
Different tree, same genus. I'm not sure if all species (of 250+) in the genus have edible fruit, but the berries of several Asian species are harvested for spices, including Sichuan Peppercorns, which are made from the dried berries.
I would bet that the flavor (citrusy, with a numbing effect) is similar among all the species, but varies in strength and pungency. I'm not sure if I would bet that any species is safe to eat, however.
I'll need to look into the ways the tree was used by Native Americans and early settlers. I have known about the use of the bark for decades but don't recall anything about other parts of the tree. Thanks for the information.
"Prickly ash" is an ingredient in Chinese cuisine, particularly Szechuan cooking. We buy it in quantity at Asian groceries where it's pretty inexpensive.
In the US it's known as "Szechuan peppercorn". Preparing it for use requires carefully inspecting a handful for stems and thorns (which can be quite big), pan toasting and crushing/grinding to a coarse powder.
As pointed out in the sister comment, the spice has a mild numbing effect which counters the heat of chilis. Adding a little to hot dishes makes the flavor more complex and enjoyable.
For people who like to cook it's an ingredient worth experimenting with across culinary boundaries.