How are flowers preserved?

In short: Preserving (stabilising) a flower means replacing its sap with a non-toxic solution based on glycerin or glycols. The flower then keeps its shape, colour and softness for several years. There are two methods, depending on the plant. The exact recipe varies by producer.

Method 1: double immersion (for flowers such as roses)

1. Fresh flowers are immersed in alcohol, which draws out their water.
2. They are then immersed in a preserving solution with dyes.
3. This liquid replaces the sap, so the flower stays soft and looks fresh.

Method 2: absorption (for foliage such as eucalyptus or ferns)

1. Freshly cut stems stand a few centimetres deep in a solution of glycerin, water and dyes.
2. The plant absorbs the solution over several days.
3. The foliage is then dried.

Is the liquid toxic? No. In cold, humid conditions a few drops may seep out. To avoid colour transfer, don't place preserved flowers directly on porous materials such as fabric or untreated wood.

How is this different from drying? Drying only removes water and replaces nothing. That is why dried flowers are firmer and more brittle than preserved flowers.