I have learned through research that you don't have to wait for the flower to completely dry before you cut it off. Dragon fruit growers say that you can cut off the drying flower a day after blooming. To be on the safe side, I waited two days. Growers also say to cut an inch or so from the tip of the developing fruit. I suggest to cut off the part of the flower that is turning yellow and be careful not to cut the part that is still green. Anything that is green will be part of the developing fruit. Some have used the drying flower as vegetable in spring roll and lumpia dish. Thank you for watching. Cheers.