Flowers

When God created trees He gave them the ability to multiply through bearing seed. For trees to bear fruit they must flower. But, do all flowers help trees to bear fruit? There are certain trees that produce very beautiful flowers but don't produce any fruit.
People have come to make use of flowers in many ways. The first of this is to create beauty. People make bouquets just for their table with flowers.
Another way people use flowers is to express love. Men give roses to their women just to say "I love you". Sometimes I don't just understand how it came to be that flowers are used to express love. But can anyone doubt that?
One of the uses of flowers that make me wonder is the wreath placed on tombs. I cannot just understand what it means.