I was surprised how easy it was to make 3-D sugar sculpture out of crushed hard candy - I started out 2-D but then was able to weld pieces together with extra blobs of melted sugar!
[CAVEAT: Looks like you'll want to store these in the fridge or something if you make them more than a day or so in advance - after 2 days in 78 degrees F and highish humidity, the thinnest palm tree dropped its fronds, and they all got quite sticky.]
I used the following method to make palm trees (to go with the gingerbread Egyptian pyramid my sister is making tomorrow, of course) but this could easily be adapted to an edible Christmas wreath. It took me about 90 minutes to make three palm trees.
Beyond the sugar trees, the lone and level sands stretch far away...
For a more traditionally Christmasy look, instead of assembling fronds to a trunk as below, you could put them onto a circular wreath substrate of melted hard candy, and add round red berries. The melted sugar has a cool glasslike effect:
1. Make your molds - I used nonstick aluminum foil (which can be hard to find - maybe normal foil would work too). To make the leaf shapes, I made a cardboard template and scrunched the foil around it (the brown oval at the right of the picture is the template, and its little leafy imprints already exist to the left, although they are hard to see). You can't get much detail beyond a general oval , but don't worry - later on you can prod the molten leaves with a toothpick to produce interesting shapes. For tree trunks, I made a furrow with the end of a pen. If you were making a wreath, I'd make a giant circle to be the base. Don't make more than 4 or 5 leaves on one piece of foil, as you want time to prod them all with a toothpick before they cool.
2. Double-bag your hard candy of choice in ziplocks, then crush it with a hammer (don't break your kitchen tile floor!)
3. Put each mold on a cookie sheet or something and load the mold indentations with crushed candy (for particularly large shapes, like a wreath base, I wouldn't bother to crush it).
4. Preheat your oven to 350 F and bake the molds for 4-5 minutes, staggered so they will come out one mold at a time. They are done when they look melty; if you leave them in a minute or two longer, they will start to brown in color, like the one in the middle in this pic:
5. When you take out each mold, use a toothpick to swirl the molten sugar into more leaflike shapes. Then let them sit until they are cool and hard enough to pick out of the mold. Put them on waxed paper (not onto paper towels, as they will be a bit sticky and would pick up a papery patina).
6. To upright trees, bake and cool the trunk first (purple + orange = brown if you swirl it with a toothpick). Then make a base by baking 3 adjacent life savers on a flat piece of nonstick foil until they start looking like a puddle. Remove from oven, stab puddle with the end of your trunk, and hold trunk upright until it hardens, several minutes (it will look solid before it actually is).
7. To attach leaves, first make an aluminum foil structure that will hold leaves in place (here, I used a cylinder that went around the trunk). Then bake a little pool of leaf color candy. Working quickly, dip the end of one leaf into the puddle (pulling out a blob half the size of a pea), then put the blobby end of the leaf onto the trunk, so that the leaf is resting on your aluminum foil support, so you don't have to hold onto the dang thing until it's cooled.
8. Clean up all the spare threads of sugar on your counter. Revel in your 3-D hard candy artistry! It's entirely edible, if a little sticky.