To appreciate flowers in English is to "admire" or "enjoy" them. This phrase likely originated from the concept of appreciating the beauty of nature and the delicate beauty of flowers. Here are a few examples of how this phrase can be used in English:

I love to admire the flowers in the park on a sunny day.

She enjoys spending time in her garden, admiring the different types of flowers.

We admired the colorful flowers on our walk through the botanical gardens.

He always makes a point to stop and appreciate the flowers along the roadside during his morning jog.