Fruit Arrangements Seen Floral Arrangements W/real Fruit In Vase. Is There A Preservative Used For This?

Seen floral arrangements w/real fruit in vase. is there a preservative used for this? - fruit arrangements

I have some beautiful arrangements of flowers and fruit in a glass vase. How can we preserve the fruit is covered with water? In particular, I saw one with lemon slices into the water and yellow roses in a vase.