[wku man]

Blackberry bushes. They provide food and a thorny and painful barrier. Unlike concertina, they grow back, too.

Scouts Out! Cavalry Ho!

[driftdiver]

I’ve seen how long it takes trained people to go across concertina wire. First guy dove on the wire, rest ran across him, last guy over pulled the first guy. Chain link fence with barbed wire on top was just as easy.

Of course most people would find it a little more difficult. I think barbed wire or thorn bushes that can catch clothing to be valuable in slowing people down.