What about cutting underwater? I’ve heard this is helpful?- Flowers 101

No. After many years of study on this method, there is no data that would support the need for cutting flower stems underwater. It was believed for many years that having the stem underwater when cutting prevented air from getting into the stem of the flower. However, cutting stems underwater transported bacteria into the water and caused the flowers to draw “dirty” stem water up the stem, thus decreasing longevity of the flowers.