Rhododendron maximum in the family Ericaceae

The scientific name of rhododendron is Rhododendron. It is a genus of plants in the heath family (Ericaceae) that includes a wide range of species known for their showy flowers.

Vaccinium macrocarpon and is a member of the Heath (Ericaceae) family.

Yes. They are in the same family (Ericaceae) and even the same genus Vaccinium. But they belong to different genus sections (sub-genera) : cranberries to Oxycoccus and blueberries to Cyanococcus.

In Botany the family Ericaceae is called ツツジ科 /tsu tsu ji ka/, but commonly heather is called ヘザー /he zaa/.