For those with mini trees, how do you "mount" them?

[Stormyblade]

So I've got 8 of the small version of the Boscoyo 360 mini trees made out of the black coro, and I've tried different things over the years and have yet to be satisfied. My front yard is not very flat and even so simply placing them on the ground ends up making them look uneven. I tried using those green plastic-coated garden stakes (just a hollow aluminum tube coated in green plastic), and zip-tied some very large fender washers in place, then just letting the bulbs/wires inside just sit on the washer, but again, no matter how careful I was, they looked uneven. This last year, I took threaded rod, clamped it to a cutout on a board that matched the bottom of the tree opening with nuts and washers, but in just one season the threaded rod (yes, they are galvanized) is all rusted and coated with white moldy stuff in the threads.

So, what do some of you use to mount your mini trees in your yard to have them look even and flat? Yard hooks? Stakes of some type? 

[StickyWicket]

I use five gallon bucket lids with a standard brick zip tied to it.  The lid has holes drilled around the perimeter to zip tie to the coro.

This keeps the tree weighed down. Never had one blow over. To get the trees straight it needed I wedge something under part of the tree.

I tried lawn staples the first couple years and hated it with a passion, they rusted and I'd lose them all over the yard.