I like to recycle Coleus and Persian shield (Strobilanthes dyerianus) in recycled beer or soda bottles, too. Threads on it here and here, if anyone's interested. Many other annuals that are actually tender perennials can be overwintered and enjoyed again the next year.

I never throw away the pots store-bought plants come in, no matter how ugly. Since I propagate and give away a lot of plants, I need a lot of pots.

Composting is the best garden recycling I know of.

My honey brings a lot of pieces of scrap wood home from work that would have went in the dumpster. He made a bat house, a dog house, using some as borders in back yard until something better looking comes along. I've used a couple pieces to "mount" and hang various artwork.

A tree in the front yard died and we used the trunk to border a bed.

Wire coat hangers can be used to get hanging plants lower, or unwound and re-bent into U-shape stakes, or used to guide a vine.

If you have trouble with plants drying out, you can use a milk jug or 2-liter bottle to slow-water it. Cut off the top so it's easier to pour into, put a small hole in the bottom. The slow drips of water coming out will soak in deeply where the plant is, not run off to other areas. A rock inside can keep it from blowing around when empty. Another version is to put a few holes along one side and bottom and mostly bury a good portion of the jug (next to it) when planting a new baby tree or shrub, maybe tomato plant. Once established, just pull it and fill the hole with dirt, or in the case of tomato, leave it for next year.