mark wrote:
Making arches and gazebos etc., by simply poking a large long cutting into
the ground.
I would like to try this having seen some examples recently.

I would appreciate some basic pointers if anyone has experience of this,
time of year, does it work with any willow etc?

Basically, yes.

However...

In dry conditions a willow can (or so I'm told) send roots a quarter of
a mile or so until they find water.

Then, usually, they break into a drain and block it up.

So, be careful.

--
Rusty