Drosera erythrorhiza is a species of tuberous rosetted sundew that is widespread in the coastal south west of Western Australia. It is the type species of the Drosera erythrorhiza complex.

Drosera erythrorhiza is a widely variable plant across its range. It reaches around 3-8cm in diameter, with larger plants in woodland environments and in the Swan Coastal Plain. Those on the granite outcrops of the south coast are smaller. The leaves are round and broad in shape. There are usually 3-5 leaves in a rosette. The flower stem typically branches and produces white flowers. The species has a propensity to form dense clonal colonies, although this habit is not present at all locations.

The species is distributed along the Swan Coastal Plain and the south coast of Western Australia. It inhabits well-drained sandy environments in heathland or open woodland environments. In the south coast, it can also be found growing in moss on granite outcrops.

Drosera erythrorhiza is part of a complex of four closely related species. It is distinguished from Drosera collina and Drosera squamosa by its round, broad leaves (those of D. squamosa and D. collina are often oval shaped and a bit longer). It is very similar to Drosera magna, which shares the same basic morphology. It is consistently smaller than Drosera magna, with a disjunct distribution terminating north of Perth (Drosera magna is larger and is found in the sand plains further north).