Living willow.

Living willow/RHS Gardening:
How to plant
Make holes first with an old screwdriver or similar, then push the rods or whips (willow stems) 30cm (12in) or more into the ground
Consider including four rods woven loosely together every 2m (6½ft) for solidity
Plant half the rods at an angle of 45° at a distance of about 25cm (10in) apart
Plant the remaining rods at a similar angle in between the first rods but in the opposite direction
The stems may naturally graft together where the stems cross together. Encourage this by tying joins together with string or thin pieces of willow
Shoots will sprout from the rods inserted into the ground. If cut back these new stems should help thicken the structure; useful if thin, one-year-old shoots were originally used to construct your feature
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