This Wreath is really easy to make. You can customize it however you like too. I have seen it with same color balloons and little Happy Birthday signs on it too. We have started a tradition in our home to put up the birthday wreath for the whole month of my kids birthdays.
So, you need a green or white plastic wreath, any size you want. At any craft store. I got mine at Micheal's.
4 large bags of Balloons. I got mine at Walmart.
A pack of Straight pins. Also at Walmart in the sewing section.
And some Ribbon to hang up the wreath with.
First you tie the Ribbon on the wreath. Then you take a balloon and fold it in half and push the pin into the balloon and then into the wreath. It holds pretty well too. You can use as many or as little balloons as you like. You can get super creative with this too. Have fun with it.