I don’t know if pumpkin plants count towards entity counts, but seeing as they are dynamically added by planting seeds, can be destroyed, collide with players, etc. I assume that they are. Whether they do or not (but especially if they do), they need to be curtailed a bit IMO. After a few days, they show up everywhere.
I would suggest adding decay (it doesn’t seem like they decay at all), lowering the number of times they can be harvested, giving out fewer seeds (lower chance per pumpkin), and add a delay to planting them to discourage people planting large number of seeds as they run.
It doesn’t seem like a big deal, but if they do count as entities, they can slow down and eventually break a server. t is nice that they are easy to destroy, but most people don’t bother and they are still easier to plant than destroy.
Maybe even give them have a small chance of returning some (1-2) cloth (a la hemp) for breaking them to encourage their destruction?