Rhododendron x hybridum

What is the appropriate use of Rhododendron x hybridum? The Royal Botanic Gardens, Kew website Plants of the World Online: that “This is an artifical hybrid. The hybrid formula of this artificial cross is R. maximum x R. viscoum.” This name also has 7 Heterotypic Synonyms.
My question is in identifying cultivated hybrid rhododendrons what is the best ID to be used? the Genus name: Rhododendron - with comments the plant is a hybrid in cultivation and not wild? Or, the Rhododendron x hybridum name which apparently is for a specific type of hybrid? Can iNat come up with a catch all for the hundreds (thousands?) of “Hybrid Rhododendrons”?

This is a problem for most cultivated plants. Many are hybrids and it isn’t always easy to figure out which species were involved or what the proper name is. I hit this issue with roses, for example.
Since the focus of iNat isn’t cultivated plants, I see no problem with just identifying the plant to genus, which is correct, and making a note with the ID that it is a cultivated hybrid.


Rhododendron x hybridum is a specific hybrid, so I wouldn’t use it for all hybrid rhododendrons.


I agree. How does someone add the information to the species page on iNat to indicate it is for a specific hybrid, and not all hybrids?

Agreed! However, there are a lot of people who are trying to identify garden hybrid rhododendrons, which is not iNat’s focus. IF, there were a generic catchall for human made hybrids, e.g. Rhododendron hybrid [human created, parents unknown] - unlike the Hybrid Rhododendron (Rhododendron x hybridum) which is for a specific human created(?) hybrid. Thanks for the comment.

Actually it looks like there is already an active flag for this. Probably best to continue the discussion there. Perhaps it would help to remove the common name.


I see a lot of ID’s recently for hybrid rhododendrons that are using the Hybrid Rhododendron (Rhododendron x hybridum) ID. I have also used it in the past, not knowing why, and for which specific hybrid this applied to.

Thanks! I didn’t see that when I searched.

see https://www.inaturalist.org/flags/599820