Better late than never, right? I made this centerpiece yesterday and instructions are below.
You'll need a container, wet foam, cutters, wooden picks, floral tape and floral wire. If you don't have all these, you can improvise.
Soak the wet foam until it is fully saturated. Usually around an hour. Cut it to fit your container, but be sure to have it extent above the container. Use water proof floral tape to attach the foam to the container.
If you want to use tapered candles, they can be pressed down into the foam. Get them in the right position to begin with, because the foam holds whatever shape you give it.
Next start adding your greens. If you are using a plain container like mine, place the greens so that they hang down and disguise the container somewhat.
Work around the container adding more greens. If you bought a bouquet from the store and it doesn't have enough greens (usually the case), you can use greens from your garden or from trimming the tree.
Keep working in the greens, using a variety for interest. Doing a good job on your greening will make it much easier to create a successful Christmas centerpiece.
Once your centerpiece is greened, start adding flowers. Place them at different heights and vary the sizes. As you work, keep rotating the centerpiece and work on the whole thing for a more cohesive look. If you work one side and then the other, it's easy to get lopsided.
You can add a bow or two if you would like. Wired ribbon is the easiest to work with. Just make a few loops and cinch it with floral wire. Then wrap the wire around the floral pick and place in your arrangement.
You can do the same thing with pine cones, decorative berries and other embellishments, depending on what look you are going for.