They're in the Terrain section, along with all other trees. They're the ones called "SPLIT2" and "SPLIT3". The editor shows them in their early mutating stage, though, not their final form.
Note that Desert theater only has one available, namely the SPLIT3 one.
General advice on how to use the editor: look at the bottom status bar of the window. It will tell you exactly what modifier keys to hold down, and which mouse button to click, to select, add, remove or edit items.
To me the mapeditor from the remastered its kinda "dumb" so i use the ccwmap to edit the TD maps and RAED-1.26 for Red Alert, and then i put them into the game folder.
its easier i think
You mean in the map editor, or in the game? As far as I know the editor shows it as mutated tree exactly like the preview.
As for the game, the thing is... they start off looking normal, and mutate from normal tree into spore-spitting monstrosity during gameplay. The amount of time before that happens is random, I believe, and it may take a few minutes.
