@joleastudio: The key is using a candleholder with a detachable top. I removed the top, then used a metal straw to carefully make a hole in the soft, watery calla lily stem. Make sure to choose calla lilies with thicker stems so the metal straw fits inside properly. This creates enough space for the stem to fit around the candleholder once the top is removed. It looks simple in the final shot, but it’s actually a very delicate process. The stems are soft and can be easily damaged, so you have to be gentle when making the hole and placing them onto the candleholder. I definitely ruined a few calla lilies while figuring this out