How to draw in perspective

Does this perspective drawing also refer to organic objects, say for example foliage, plants? Do you just draw out the plant directly but follow the direction of the vanishing point to keep the correct perspective or do you make a box first according to the vanishing line and THEN draw the plant? Does it matter which direction the plant is facing? Can it still be in correct perspective although the foliage sticks out in different directions?

Very thankful if you answer, I´m currently really starting to understand how perspective works, but I still have much to learn