Hi. I’m garden editor, Jane McKeon. Today, we’re prepping dahlias for bouquets. Did you know that blooms will last longer if you condition them first? Dahlias are one of the few flowers that won’t open further once they’re cut. So, wait until the buds are fully open before you gather them from the garden. Harvest them in the early morning, the coolest time of the day. To condition the stems, pour two or three inches of very hot water into a metal bucket. Use a candy thermometer to check if the water is hot enough, between 160 and 180 degrees. Make sure you strip off the bottom leaves before you put dahlia stems in the hot water. Keep the flower heads well above the rim of the bucket to protect them from steam. For short stems, you can use a coffee can. Once the water has cooled– in about an hour– dahlias are ready to arrange. To keep dahlias looking fresh, change the water every day. With these simple steps, dahlias can last up to a week in a vase. Enjoy.
SOURCE:http://www.bhg.com/gardening/flowers/bulbs/dahlias-in-bouquets/