Fill the bucket with warm water and take it with you out to the azalea shrub early in the morning on a day with pleasant weather.
Examine the plant to find buds that are almost ready to open. Clip off the stems of these buds, making them as long as possible. Place the stems into the bucket immediately and continue cutting azalea stems until you have as many as you need.
Hold the ends of the stems under warm running water and cut the ends off at a 45-degree angle. Make a small slit in the end of each stem to help them absorb water more readily. Remove any leaves from the bottom portions of the stems so there will not be leaves beneath the surface of the water. Refill the bucket with fresh warm water and place the freshly cut stems back into the warm water.
Leave the stems in the bucket for approximately three hours before arranging. Place the bucket in a dark room during this period. The buds will begin to show color when they are ready for the final arrangement.
Fill the vase with cold water and dissolve the floral preservative in the water. Add the azaleas to the vase of water and place the vase in a room where there is bright, indirect light. Change the water every other day, adding additional floral preservative each time.