Make Your Own 12 Stem Flower Rose Centerpiece

This is a beginner-level arrangement. With proper preparation and planning, you can expect to complete this twelve-stem Demi centerpiece in about 10 minutes.

Materials
To create the centerpiece, you'll need the following items:

12 fresh roses.
Sharp utility scissors.
A 4" glass rosebowl, available at craft supply stores,
Hex wire or chicken wire, available at home and building supply stores.
Lightweight wire cutters.
Spray bottle filled with clean water.
A tall kitchen garbage bag.
Preparation
Prepare each rosebowl by cutting one piece of the chicken wire into a 4" by 8" strip. Roll it into a tube shape and twist the ends to secure. Insert the tube into the rosebowl and rotate it 90 degrees (horizontally). You might have to bend the ends to make it fit securely inside the bowl. This wire form will help hold the stems in place when you assemble your flower arrangements. Repeat for the number of rosebowls you are using.
Recommendation: If there are many rosebowl containers to be readied, consider preparing all of the wire inserts well in advance of the wedding day. If you complete that job beforehand, you will have more time to enjoy the fun part - actually arranging the flowers hours before the ceremony...
The day your roses are delivered remove all foliage and snip the tips of the thorns if your roses have them. You may also want to read How to Care for Fresh Roses for more tips and tricks.
If you are doing more than one or two arrangements, enlist the help of a few friends and relatives. They will help the project move faster and keep the focus on fun.
If you are planning a morning or early afternoon wedding, add the roses to your centerpiece the night before. For a late afternoon or evening wedding, plan to assemble the roses early that morning.
Instructions
Fill the rosebowl with clear warm water.
Using the utility scissors, cut the stem of one rose at a 45 degree angle about 6" below its head. Place the rose in the rosebowl with the stem resting on the lip and the head about 1/2" over the edge. The chicken wire will help to hold the stem in place. Repeat with five more roses, placing them close to each other. If there is space between the roses, trim the stems again to make a smaller circle. When finished, you should have a circle of roses about 8" in diameter.
Using five more roses, make a second inner circle that is slightly smaller than the first. They may not all fit directly next to each other which is perfectly fine. Just stagger them to fill in.
Trim the one remaining rose and place it in the center of the arrangement. Adjusting to eliminate any gaps.
Spray the arrangement lightly with water.
If you have space, place the arrangement(s) in a refrigerator covered loosely with a plastic bag. If there's no room in the fridge, don't worry; your flowers will be absolutely fine if you keep them stored in your workspace.
Success Tips
Blow a puff or two of air - as if you were blowing out a candle - down into the center of each rose just before adding it to the arrangement. This helps the petals open out a bit more and gives a fuller look.
When you are cutting stems, it is best to snip them a little longer; you can always trim them shorter if necessary.