Very nice flower. I'm glad you're not going to leave it gray.

I'd find a pipe that your flower stem will just fit into. Bury the pipe in the ground so the top is somewhat higher than the soil level (ideally the top would be hidden by other plants). Tamp the soil, wet the area around the pipe, then let it dry thoroughly. Then simply insert the flower stem.

I've no idea how long the pipe should be; I imagine it would be dictated by the type of soil you have and the weight of the ornament. And if you eventually need to remove the pipe, I don't know how you would do it.

If the flower tends to lean, you could dig a larger hole and pour concrete around the pipe (being sure not to insert the stem until the concrete is cured).

The above is entirely theoretical: I've never done it. But I've read about similar methods of securing seasonal structures like veggie trellises. Sometimes a pipe fits over a re-bar anchored in the soil; sometimes a smaller pipe fits into a larger pipe set into the soil.

If you don't get a better answer here, you might cross-post on the Garden Junk forum.

Thanks for the reply! I really like that idea. Our soil is clay, so I would like to think that just pounding a pipe a foot or two down would be sturdy enough. The flower isn't horrifically heavy. My guess is maybe 10 lbs.

And thanks for the recommendation about the garden junk forum. You're right, they make a lot of garden art over there and probably have some good experience to share. I hadn't even thought of that forum!

It's not impossible to have a movable heavy object but you create competing properties-- an easily movable spiky garden ornament is best as something light and thin that you jab into the soil , as you were originally thinking. The pipe " holder " of your now heavy flower adds permanence and reduces options of moving on a whim. So many choices!

Well, it doesn't have to be too easily moveable. I just wanted something less permanent than poured concrete. I think I might go with a larger piece of rebar, driven into the ground. Then I'll wire this one to the rebar in some decorative way with heavy gauge wire. I'm thinking that would work, and allow me to move/remove fairly easily if I needed to.

The Hypertufa forum might help you to make the next ones somewhat lighter. I think they use concrete mixed with peat moss, or other organic stuff, to lighten the weight of their ornaments.