The same happens with the watermelon trope. Some slaves were allowed to grow their own food and, because of easiness, a lot of them went for watermelon. When the ACW finished there was a big pool of ex-slaves watermelon farmers with the know-how to flood the market. From what I read, it was common to see in the 1860s-70s black people selling watermelon in stalls in the Southern roads.
It was common to see all kinds of people selling them in stalls and out of the backs of pickups and farm trucks all over Texas into the 1970s and beyond - you can still find them around in some places today. All folks, though, not just those of African descent - we grew them ourselves, but only for us and friends. We did sell rabbits, though, usually to the feed store, but occasionally out the back of dad's El Camino.
Being close to the Gulf, and being Southeast Texas, you'd also find folks selling shrimp & crabs the same way, other Gulf seafood as well (at least within about 40 miles of the coast), and tamales - when we'd travel down I-45 to Pearland to visit dad's brothers, we'd always exit at Dixie Farm Road and see which trucks where there, as you could usually find both a shrimp truck and a tamale truck - sometimes the same truck! That's within about 25-30 miles of Galveston where the shrimpers would come in. And if it was for our family Labor Day weekend get together, we might grab a couple of watermelons and some cantaloupe because there would probably be a truck selling those at that same spot.
It was just the way things were done throughout much of Texas and many other states with heavy agrarian populations, coastlines, or a big mix of ethnicities. I think it's where the modern "food truck" culture was born, in part at least. It was almost always fresher than the grocery store and usually better since things like the watermelons were picked and sold when ripe, rather than a week ahead to make it to market. And for a while, it was about the only way you found good tamales unless you knew someone since they weren't really a broadly available grocery item until, maybe, the last 20 years or so. Still best to have a connect, though: nothing like someone's abuela's recipe. We of Germanic descent might trade them for homemade sausage - made everyone happy.
