Fresh flowers and plants are given as symbols of caring, friendship, love, remembrance and other sentiments. And although this is true year-round, the Society of American Florists says that Valentine’s Day tops the list for sales.

Have you ever wondered how flowers became unspoken words, or why they are so popular as gifts?

The history of flowers’ symbolism varies over time and with different cultures. Many of the meanings associated with flowers in the U.S. today stem from a cultural movement in the 1800s. Here and in Britain and France, flowers and plants became formally tied to the idea of sending coded or unspoken messages, and multiple floral dictionaries were published to explain what each flower meant.

The floral dictionaries published in the 1800s gave varying opinions about which flowers best represented which sentiments, depending on when and where they were written. Modern versions have alleviated some of the discrepancies and highlighted the symbols that have stood the test of time.

A few of the most common ones: Red roses symbolize romantic love; yellow roses symbolize friendship. Pink roses and carnations are for care or appreciation. White roses and carnations represent purity and remembrance. White tulips are a symbol of forgiveness. Forget-me-nots offer their message in their name.

Around the time the floral dictionaries were being published, the floral industry was limited by lack of refrigeration and transportation. In Europe, most flowers were grown in the Netherlands and transported to other countries, but Americans were much more likely to buy their flowers from a local farm. Not only were flowers perishable, but U.S. growers were severely limited by seasonality, which meant that fresh flowers in February would have been a rarity for much of the country.

Eventually, shipping systems were developed that allowed flowers to be transported long distances over short periods of time. Shipping containers held flowers at a constant temperature, and they could be refrigerated once they arrived at their destination. The Netherlands, with its longstanding experience in flower production, began supplying flowers for much of the world. Roses and carnations grew in popularity because they held up better in shipping and lasted longer in arrangements than many other species.

In the 1990s, some flower production shifted to warmer climates with lower labor costs. Today, almost all of the roses sold in the U.S. around Valentine’s Day are grown in Colombia and Ecuador. In recent years, fair-trade, local and U.S.-grown labels have grown in popularity, but they still hold comparatively little market share. Check with local florists or seek out local flower farmers for these options if desired.

Flowers and plants are still symbols of love, friendship, caring and other sentiments, but it’s wise to assume that not all people today agree on what specific kinds of flowers mean. If you want to send a message with your flowers, writing it down on a card might be the best option.

— Jennifer Smith works in regulatory horticulture and has worked as a horticulturist for various government entities. She has experience in landscape design and maintenance and as an educator.