Through (Toolbox-Landscape-Flora-Auto) you can control the automatic spawning behaviour of the vegetation in the biome.
You have (per layer) control over each category such as:
Trees
Grass
Rocks
Foliage
Debris
Where for each of them you can control values such as:
Density
Altitude Range
View Distance
Follow Ground Slope
Spawn Angle
MANUAL:
If you want finer control over vegetation placement, you can go to the (Toolbox-Landscape-Flora-Auto) tab and then choosing the vegetation object you want and place it like you would place any normal object in the scene and then move, rotate and scale it as needed.
