Growing sunflowers (Helianthus spp.) at home gives you constant access to beautiful blooms you can cut and display, but how you cut and care for them affects how long you can keep sunflowers alive in vases. Choosing the ideal time to cut sunflowers can help them stay perky and beautiful for longer. Cut sunflowers can usually last six to 12 days once cut depending on how fresh they are when you cut them and how you care for them.
Choose the Best Sunflowers
Don't wait too long to cut sunflowers. The ones that will last the longest in your vases are the ones with petals that are just starting to open up off the face. If the sunflower has already opened completely, it's life is already a lot shorter once you cut it. Look for the strongest, healthiest-looking sunflowers that are just starting to open.
Water Before Cutting
Sunflowers are always thirsty, so keeping them well-watered while they grow prevents them from drooping before you cut them. When you know you want to cut sunflowers, give them a good drink a few hours beforehand. This prevents them from looking wilted at the time of cutting and ensures the stems and flowers are well-hydrated.
Cut Your Sunflowers
The best time to cut sunflowers in order to keep them alive in a vase is in the morning. If you cut them in the afternoon, the flowers are more likely to wilt due to the heat. Heat or water-stressed sunflowers won't last as long. Prepare a bucket of warm water to keep next to the plants so you can put the cut flowers in water immediately.
Use sharp pruning shears or a knife to cut the stems at a 45-degree angle. The angled cut gives the stem more surface for taking in water. Leave the stem long enough to fit into your vase. Remove most of the leaves except the ones right under the flower. You don't want leaves to sit under the water, as they can rot and shorten the life of the sunflower.
Place Sunflowers in a Vase
Once you get the sunflowers inside, keep them in the bucket of water in a cool place for several hours to help condition them. Then, place them in a clean vase. Dirty vases can have bacteria in them from previous bouquets, and this can shorten the life of your sunflowers. Use room temperature water for best results.
If you have plant food for cut flowers, add it to the water. You can also add a teaspoon of sugar and a few drops of bleach to the water to make the flowers last longer if you don't have flower food. Ensure the water level in the vase stays high. Add more water as needed to ensure the sunflowers don't run out.
Change the water and clean the vase every two to three days to extend the life of the cut flowers. Replace the water sooner if it looks cloudy. Rinse the sunflower stems when you change the water and add more plant food or sugar and bleach to the fresh water. You can also recut the stems under the water at an angle to help the sunflowers better take up the water.
Choose an Ideal Location
Where you choose to display your cut sunflowers can affect the vase life of the big yellow blooms. Though sunflowers love to soak up the sun while they grow, placing cut sunflowers in direct sunlight can make your arrangement short-lived. Bright, indirect light can help keep sunflowers alive longer, and the blooms usually do best in cooler spots. Watch out for drafts or anything that produces heat, as this can dry out the cut sunflowers. Even ripening fruit near the sunflowers can shorten the life of the blooms due to the ethylene gas it emits.
Shelley Frost combines her love of DIY and writing in her freelance career. She has first-hand experience with tiling, painting, refinishing hardwood floors, installing lighting, roofing and many other home improvement projects. She keeps her DIY skills fresh with regular projects around the house and extensive writing work on the topic.