Here’s some good viewing on making Bayou swamp terrain.
modeling
Bag End Bonsai How to
It’s not miniature wargaming, but fans of Tolkien and miniatures in general will love this Bag End Bonsai.
Modeling Shrubs
The Mordheim in Montana blog has an illustrated article on making bushes and shrubs for your 25mm wargames.
Making Expanding Foam Hills and Rock Clusters
Here’s a nice tutorial on making cheap and easy expanding foam hills for your wargames table.
Advice On Basing Wargames Figures
Arcane Scenery has a nice blog post on basing your wargames figures with Vallejo 26218 Darth Earth paste. I have never seen this product before, but I really like the way it looks.