Wash out the buckets with a solution of 1 tbsp. of household bleach to 1 gallon of water. Let the solution stay in the buckets for at least 60 seconds then empty the buckets.
Fill each bucket with ice water. Leave one bucket on the patio or in a shady place.
Cut the flowers with as much stem as required. Taller arrangements require longer stems than short floral arrangements. Place stems immediately in a bucket of ice water. Wipe off the shears with a disinfectant handy wipe as you go from plant to plant.
Treat any flowers with special requirements. Poppies and hollyhocks will wilt if their stems are not cauterized with a flame; daffodils need to be in their own container for an hour or they can cause other flowers placed with them to wilt; amaryllis have hollow stems that need to be filled with water.
Carry the bucket of flowers back the bucket in the shade.
Remove the leaves from the portion of the stem that will be underwater in the vase. Re-cut 1/2 inch of the stem and place it in the empty clean bucket of ice water. Leave the flowers in the ice water for 60 minutes. This conditions the flowers much like putting limp celery in ice water to crisp it up again.
Bring the flowers into the kitchen by a sink. Fill the sink with water. Fill the vase with ice water. Clip the bottom of the stem 1/2 while it's under water. Immediately place it in the vase. Arrange the flowers in the vase.