can you change a plantsim's hair?

Elianapaster, you can't change a PlantSim's hair as far as I know. ☹️  I have tried changing one's appearance in the "Plan Outfits" option in both the dresser and the mirror, but when you try that it just shows the Sim as they normally are, with no PlantSim options! 😞 Furthermore, every PlantSim that I have seen has the same exact hair, whether male or female, young or old.  The only time there was any change is if your PlantSim gets really dehydrated, and then the "hair" goes pale, as if it looses color (almost like gray hair), but that is quickly remedied by hydrating your Plantsim. 🙂  My guess is that a PlantSim doesn't really have hair but he/she/it has leaves on the head instead!  Coincidentally, a pregnant PlantSim will give birth to a normal baby, so unlike The Sims2, there are no Plant Sim babies (although I didn't try to have them eat the Forbidden Fruit, so who knows?!?)  LOL 

Perhaps there might be a Mod you can get that will let your PlantSims have hair you can change, it might be worth a look!  😉  Best of luck, and Happy Simming!