You can Crossbreed many flowers in Animal Crossing City Folk but there is special ways you may not know about but here is some help if you need it check out the website.
Just plant different color/species plants adjacent to each other and hybrid flowers will popup next to them. And the color for the hybrids are a mix of the original's colors
You can only make hybrids on animal crossing wild world.
View the link below for the answer.
Flowers, Flowers, And Flowers...
The Kinds Of Flowers are Gumamela flowers,
how many kind of flowers are there
More than2,500 flowers
dead flowers.
no trees are plants and some of them dont have flowers
Elms
flowers
white flowers (carnation)
compare the different kinds of animal population
Violets. Verbena.