If you planted them as a clump, you may put stakes around perimeter and tie a twine to make a circle. If you planted them as a row, you need to place stake at the beginning and the end of the row and a few in between (depending on a lenghts of your row) and tie a twine all around. It doesn't make sense to stake individual flowers. You would need to do staking when they'll be 18-24" tall depending on variety and move twine up as they grow. In your zone 10 they will live for many years without digging and replanting, so if it would be me, I'd plant them as deep as 10-12", not a 6". Deep planting helps to either completely eliminate or just reduce to ocassional staking of individual plants for shorter varieties (up to 30" tall). 36 to 48" tall varieties probably would need staking anyway.

My thought would be to drill a few inches into the bottom of the spindle and then insert re-bar into the hole and then stick the re-bar into the ground. If you are worried about moisture, you could seal the inside of your new hole with deck sealer. If you are looking to extend the wood part, you could get a new spindle, and drill into both the old and the new and connect them with a dowel.... that way the new spindle will rot away instead of the one you have. In fact, a dowel inserted into the end of your spindle could be mounted into anything... an old lamp base comes to mind.

If that root is an adventitious root, it's a result of the tree being planted too deep by the grower back when he panted the tree out in his field. I don't see any possible way that it could have grown that large in just two years. I personally would not consider removing any more dirt from around the trunk, if it were my tree and I was working with it. I would remove the border (as ademink previously suggested in the other thread). There's nothing bad about an adventitious root, although it may have resulted for a condition like being planted too deeply. In that case, it's an attempt by the tree to adjust to its new conditions. After considerable adjustment has already been made, "fixing" the original conditions can be counterproductive, or worse. Dan also brought up a good point that many Acers adapt more easily to grade change than many other genera. Any tree can potentially have girdling roots and the presence of adventitious roots doesn't necessarily correlate with girdling roots. Trees without adventitious roots often have girdling roots and trees with adventitious roots don't necessarily have any higher chance of having girdling roots. Mackel, sorry, but I don't follow your lack-of-scientific-reasoning statement. I thought I presented my basis for thought as well as you did. Any any event, different opinions are fine and often helpful.

I had the same problem! When I bought the plants my husband suggested to use only a 4 foot cage. I told him that I have read that plants can get up to 10 feet tall if not taller. Well I didn't push too hard and went with the smaller cages. Now my plants are well over 7 foot tall and my husband had to build a cage to go around the existing cages. He built it out of wood we had left over to make the raised bed. It is massive, but it works. We were able to put side rails at different heights to encourage the growth upward and over. However, my plants are not done growing. They will outgrow the massive cage and at that point they will have to just drape down. So you could build a bigger, bulkier cage out of wood or PVC or some other material of your choice for this year and use it as a learning experience, as I have, for next year. I don't think I would ever try staking after seeing how jungle-like my plants have gotten. Good luck!