Hi,

For me the best option for what you asking for would be to use Blender with specific addons.

Have a look there :

https://www.blender.org/download/

https://inspirationtuts.com/blender-plants-addons-vegetation-asset-packs/

https://blender-addons.org/vegetation-addon/

I do love nurbs based software like Moi3D that i use often, but unfortunately nurbs have some limits for some tasks.

Cheers