This Very Blog has a very good set of instructions for building hedgerows for 25mm – 28mm figures. This is the best set of instructions I have found, and the one I will use for my Normandy terrain.
hedgerows
Making Field Dividers / Hedgerows
Small World Productions has a photo tutorial on making hedgerows and field dividers.
Hedgerow Photo Tutorial
The One of My Men Became Restless Blog has a photo tutorial on making hedgerows. I have threatened for years to make hedgerows, and yet never seem to find the time.
Making Hedges With Plasticard and Clump Foliage
Here’s another tutorial on making hedges — useful for lots of different settings.