In July and August, the cheerful golden blooms of Black-Eyed Susan grace the garden. But before we talk more about them, we need to get something figured out: which Black-Eyed Susan, exactly, do you have in your garden? There are two very different plants that are both commonly called “Black-Eyed Susans,” (one example of why those pesky botanical names are sometimes necessary to know!) and they have very different attributes. We grow both of them in our garden, so let’s take a look at each.
Black-Eyed Susan #1: Rudbeckia hirta
Rudbeckia hirta is a native biennial or short-lived perennial, depending upon conditions in your garden. It grows anywhere from one to two feet tall (sometimes taller) and spreads via seeds. Each plant is composed of a basal rosette of foliage, and flower stems, each with a single bloom, emerge from the rosette. R. hirta blooms in late summer to fall. It tolerates a wide range of conditions, from full sun (which will result in taller plants with more blooms) to partial shade. It is not overly choosy about soil, though it does best in well-drained loam. In our garden, they’re managing just fine in soil that is mostly clay that we have amended with a topdressing of shredded leaves each fall.
R. hirta can become somewhat invasive if it is happy in your garden. We’ve had seedlings popping up in the lawn and in sidewalk cracks, so that is something to keep in mind regarding this particular Black-Eyed Susan. Another thing to note about R. hirta is that its foliage is fuzzy:
The leaves show some serration, but, as you’ll see when we look at the “other” Black-Eyed Susan, the foliage is definitely different, and is possibly the easiest way to tell the difference between the two.
Black-Eyed Susan #2: Rudbeckia fulgida
The blooms above are from the second type of Black-Eyed Susan, Rudbeckia fulgida, which is also commonly known sometimes as “orange coneflower.” Pretty hard to tell the two apart just from looking at the blooms, isn’t it?
R. fulgida is a perennial that grows into clumps about three feet tall by three feet wide. It grows well in both full sun and partial shade, and, while it isn’t picky about soil, it does best in moist, well-drained soil. R. fulgida blooms in late summer, just like R. hirta. In fact, both are blooming in my garden right now, in early August.
R. fulgida spreads by seeds, and you can also divide the clumps (which can expand quite a lot over a few seasons!) to make new plants. It is not nearly as likely to become invasive as R. hirta is, so if you’re looking for a well-behaved, low maintenance Black-Eyed Susan, R. fulgida would be one to look for. How to tell it apart from its prolific cousin? Again, take a look at the leaves. Where R. hirta has fuzzy leaves, R. fulgida’s foliage is smooth, and shows more serration at the edges:
(As you can tell from the photo, R. fulgida is also more attractive to insects. The plant is still growing robustly, though, so I don’t worry about it.)
I hope this helps you tell the difference between the two, and helps you decide which is a better fit for your garden.
What to Plant with Black-Eyed Susan:
Several plants look great planted with Black-Eyed Susans (of either type!) They include:
- Purple Coneflower (Echinacea purpurea)
- Blazing Star (Liatris)
- Garden Phlox (Phlox paniculata)
- Annuals, such as zinnias, marigolds, sunflowers, and cosmos