Vegetation is used to better enhance the map you make in Stronghold 3. The available types of vegetation are stated below.
Additionally in the Vegetation section is the ability to alter the brush size and the brush intensity. The intensity of the brush is how much vegetation you add to the map in one go. There is one other tab which allows you to add shrubs to your map. These can be useful for rivers and water. Here is a list of all shrubs in the editor:
In Stronghold Crusader 2, the following Vegetation is used:
The following image is an example of what the flowers look like:
There is also another section entitled "Shrubs", which contain the following shrubs:
One other sub-section is in the Crusader 2 editor, which is entitled "Rocks". This allows you to place the following boulders: