Thunbergia alata, also known as Black-eyed Susan vine, is a beautiful and versatile plant that is often confused with the true Black-eyed Susan (Rudbeckia hirta), which is a different species altogether. While they both have the common name “Black-eyed Susan,” they are actually unrelated and belong to different plant families.
Thunbergia alata, or Black-eyed Susan vine, is a herbaceous perennial climbing plant that is native to Eastern Africa. It has vibrant, trumpet-shaped flowers with a dark center or “eye” surrounded by bright yellow, orange, or white petals. The vine has a twining habit, meaning it wraps around and climbs up structures or other plants for support.
On the other hand, the true Black-eyed Susan (Rudbeckia hirta) is a perennial wildflower native to North America. It belongs to the Asteraceae family and is known for its daisy-like flowers with a dark brown or black center and yellow or orange petals. It grows in clumps and doesn’t have a climbing habit like Thunbergia alata.
Despite the confusion in their common names, Thunbergia alata and Rudbeckia hirta are distinct plant species that are not closely related. It’s important to differentiate between the two when discussing or purchasing these plants to avoid any misunderstandings.
In my personal experience, I have encountered this confusion numerous times when discussing Black-eyed Susans with fellow gardeners and plant enthusiasts. It can be quite frustrating when trying to communicate about a specific plant and realizing that we are actually referring to different species. This is why it’s crucial to be clear and specific when using common names, as they can vary and lead to misunderstandings.
To summarize the main differences between Thunbergia alata (Black-eyed Susan vine) and Rudbeckia hirta (true Black-eyed Susan):
Thunbergia alata (Black-eyed Susan vine):
– Belongs to the Acanthaceae family
– Native to Eastern Africa
– Climbing vine with twining habit
– Trumpet-shaped flowers with dark center and yellow, orange, or white petals
Rudbeckia hirta (true Black-eyed Susan):
– Belongs to the Asteraceae family
– Native to North America
– Grows in clumps, not a vine
– Daisy-like flowers with dark center and yellow or orange petals
Thunbergia alata and Rudbeckia hirta may share the common name “Black-eyed Susan,” but they are different plant species with distinct characteristics. It’s important to be aware of these differences to avoid confusion and ensure that we are referring to the correct plant when discussing or purchasing Black-eyed Susans.
