We placed ours underneath a tall arbor and wired it to the top of the arbor as well as staking it into the ground.. Have had it for several years and it's stayed in place just fine despite the winds we have here. Also leave the bottles in place year round and not one has ever blown off or broken.
I would like to include a picture but don't see the "browse button".

I dug a hole in the ground for mine I just did it friday and hope it stays ok haven't had a problem before with this method

I'm having one made ,too -- out of a real tree. I wasn't sure how to anchor it either. My flimsy metal one bent in the wind. The only solution I see is dig it real deep. Good luck with yours!

This is a big hunk of Manzanita tree. It's buried a few inches in the dirt. We cut apart a metal bed frame (website with bed frame photo below) and pounded two long pieces of the side rails about 4 feet into the ground, leaving about a foot above, then wrapped them and the trunk with plumber's tape (plumber's tape is metal banding with holes in it). We put some screws into the tape. It's held up very well. Elbow grease is needed for this job, lol.

Rebar can be pounded into the ground and wired to the tree.

If you have some sort of roof or frame above it, wire can be run up and fastened to stabilize it.

A concrete footing will also work.

Linda

{{gwi:141026}}

Here is a link that might be useful: Photo of metal bed frame

I curbshopped a floor lamp. The black metal ones with the 'bowl' top and heavy bottom. I took out the electrical parts and dug a hole and put the heavy metal bottom under the dirt a bit. The weight alone kept it pretty secure. I used copper pipe I had and curled it around a large pipe and stuck one end into top of the metal where I removed the 'bowl'. Then I stuck the bottles at the end of each of the curled copper pipes. Also my hubby kept some heavy metal circles from auto wheels and I use them to anchor a lot of things into the dirt.

My hubby drilled a hole through the trunk and inserted a heavy rebar rod which we stabbed into the ground a couple of feet. We have sandy soil so that may not be as easy for those dealing with clay or rock.