The Core Cape Subregion is one of the world’s smallest but richest floral kingdoms, encompassing a land area of approximately 90 760 km² (less than 4% of the southern African subcontinent). An estimated 9 383 species of vascular plants (ferns and other spore-bearing vascular plants, gymnosperms and flowering plants) are known to occur here, of which just over 68% are endemic. The majority of these species are flowering plants. The Core Cape Subregion is characterised by six endemic or near-endemic families and by the conspicuous presence of Asteraceae and Fabaceae (two of the largest families) and the Iridaceae, Aizoaceae, Ericaceae, Proteaceae and Restionaceae. The Core Cape Subregion is notable for its range of ecosystems, ranging from coastal foredunes through strandveld as represented in De Hoop Nature Reserve, and lowland and mountain fynbos as represented in Riviersonderend Nature Reserve Complex.

De Hoop Nature Reserve displays the floral wealth of the Agulhas Plain Centre (one of the six phytogeographic centres of the Greater Cape Floristic Region) that has an endemism rate of 14.9%. Some examples of special plant species include a very interesting species of which only a handful of plants have ever been found in the De Hoop Nature Reserve, Gladiolus vandermerwei. The lollypop conebush, Leucadendron immoderatum, is a species listed as critically endangered that occurs within the Riviersonderend Nature Reserve.