Over 8,500 different species and varieties of plants are to be found at the botanical gardens of Wilhelma. Varieties are not true-bred species, but are breeds or cross breeds of different species. In this way a huge variety of different blossoms can develop in the plant world, for instance in orchids or camellias, which have been bred from only few species.

Wilhelma is famed for the amount and variety of orchids, camellias, bromeliads, fuchsias or cactuses and succulents in its possession. Plants that come from a related group are gathered together in so-called botanical collections. This is a sort of living herbarium: not dead and dried plants, but living ones that can be propagated and raised.

And so the field of the botanical gardens does not only consist of the display houses where plants are on show for the visitor. A large separate horticultural department with various glasshouses is also part of this field.