Red ones mean passion and romance, yellow ones speak of friendship, and pink can express your thanks.

红玫瑰代表热情和浪漫，黄玫瑰象征友谊，粉玫瑰则表达谢意。

Bloomin' marvellous: Rainbow roses are non-artificial flowers also known as the happy rose. It uses a groundbreaking process where vibrant coloured plant extracts are injected into the stem.
If you're feeling a little confused - or you want to keep a lady guessing - you could try sending these roses instead.

The multi-colored flowers, known as rainbow roses or happy roses, are the latest thing in quirky（古怪的，离奇的） gifts.

They start life as cream roses, but the heads take on hues（色调） from various food dyes（食用染料） placed in their water one at a time and sucked up（吸收） the stems.

We know the process takes between 12 and 24 hours, but not how the different petals（花瓣） turn out different colors.

That remains a trade secret of their creator, Dutch florist Peter van de Werken, who branched out from creating brightly colored chrysanthemums（菊花） .

He buys long-stemmed Vendela roses, dyes them and distributes them around the world. They still have their sweet smell and the flowers will last as long as normal roses, but the leaves may wither（枯萎，凋谢） sooner.

More than a million were sold in a year, with key markets in Japan, Italy and particularly Sweden, where blue and yellow varieties mimic the national flag. Britons can buy them at online florist（花商） Interrose.co.uk.

However, they do not come cheap. One stem costs £24.49 and a dozen £64.87, more than double the price of 12 red roses.

So maybe they do send a simple message after all - you're worth it.