For this project, we are making giant mushrooms.  

I choose to make the base of the mushroom out of OSB wood cut into 1 foot squares various sizes of PVC pipe anchored to those for the stems.  The tops are a mash of various paper mache, chicken wire and hardware cloth, aluminum pans, joint compound and paints, and even a dash of expanding foam.

To get a variety of mushroom sizes, I chose to use a couple different sizes of PVC pipe, cut at various lengths and even some smaller 8 inch concrete tubes.

I started by screwing the PVC into some 1 foot square OSB wood.

and then adding joint compound to the base to give strength and to hide the hardware.

The next step was using either chicken wire or hardware clother, or roasting pans from the dollar store, to make the mushroom heads, then paper macheing over those, covering them in joint compound

To give them a little more texture, some spray foam was added to look like growths along the stems and the heads.

And then finally they were painted various colours.

 Some of the heads were too heavy and flopped over during drying, which added more to the variety.