@ Stan

ZBrush is great for some static plants but it's not going to be a sollution for animations or speed. I agree Plant Factory is overpriced but it's also very powerful and truly easy to use thanks to the UI.

XFrog Basic is not much and lately it is at half price. It's also great for modeling plants and easy to use. I use it a lot and highly recomend it.

ZBrush is not a good answer if you need a forest of unique plants that will react to the wind in an animation or even in a still. ZBrush would not be of much use.