I live close to a rather large lake and have planted inside old hollow stumps still sticking out of the water. This was risky as the lake is used by many other ppl. I stopped doing this many years ago, but It was always fun to hide it in plain sight!
Another place I planted, and still do is along "Right of Ways" beside powerlines. Around here, there are trails that go along under the lines, and I will either ride my atv or a horse w/ saddle bags if I needed to carry something out or back home. and I plant no more than 2 in the same area, and hide them within the tall brush. This is also like hiding in plain sight.