Caring for cut hydrangeas Cut hydrangeas will sometimes wilt almost as soon as you bring them in from the garden. Either the sticky sap in the stem or trapped air bubbles can form a barrier that prevents the flower from taking up water. Some techniques that will help prolong your blooms: -- Cut flowers in morning or evening, when it's cooler. -- Bring a container outside and place stems in water as soon as you cut them. -- Give stems a quick hot-water bath. Boil water and pour it into a container. Hold the bottom few inches of your hydrangea stem in the hot water for 30 seconds, then transfer to a vase with room-temperature water.