Failed piles to arrange the tree

I failed to arrange the tree in my backyard before. I cut an old broom to 3 pieces.

The ground was too soft to support the load of the slanted tree.

The gold crest was slanted again. I tried restoring upright. I looked for bamboo at a DIY shop near by. The shop doesn't sell such bamboo. I thought a very old broom with bamboo rod.

I cut it down 3 parts easily by saw. The rod dried up completely.

I fixed them as below. But the two piles loosened the next day. They were too short to support because of soft ground.