I made some garden stuff using alder that grows on my property. I made fence panels, some trellises and an arbor.
It's better to use fresh wood as it is easier to nail it. I used panel nails that have rings on the nail for better holding. Do a design on paper first, cut your pieces and nail. It becomes addictive.

I found that it is much better to screw them together or it gets wobbly - especially if it is freestanding, like an arbor. I also pre-drill the holes to prevent splitting and use any limbs I can find, not picky about variety. See what I have made here at my garden photos link.

Here is a link that might be useful: link