Make a Dead Hedge
From: DK Books - How to Grow
Use strong, long-lasting poles for the uprights, hammering them securely into the ground. For a neater look, use lengths of willow to weave loose sides. Then simply pile in shrub trimmings, lengths of ivy and bramble, and any other twigs the garden produces. Eventually, they will rot or compact down, and you can then add more to the top.
Tip: Create a Log Home
A pile of old logs in the garden will attract beetles, frogs, toads and other wildlife. Make a well-constructed pile, supported by a few posts hammered into the ground to prevent rolling. Leave the logs to rot down.