Black-eyed Susan is a flowering plant found all over the U.S. Before planting, you may wonder if this plant is considered invasive. In this article, we will answer if black-eyed Susan is an invasive species and much more.
Due to the native nature of black-eyed Susan, this plant technically is not considered invasive. However, this flowering plant does spread rapidly and can become invasive to your garden and other plants.
You know that black-eyed Susan will need special care because of how it spreads, but what does that care look like? Keep reading as we discuss how you can keep black-eyed Susan from spreading and more.
Is Black-Eyed Susan An Invasive Plant?
The definition of an invasive plant is one that is non-native to the ecosystem, and whose introduction is likely to cause economic or environmental harm.
Black-eyed Susan [Rudbeckia hirta] is native to Eastern and Central North America. This plant grows in all 48 states, as well as all 10 Canadian Provinces.
Because this plant is native, it cannot be considered an invasive species. However, this plant does have invasive properties. These properties include the production of large quantities of seeds and aggressive root systems.
The mentioned properties are why you should plant black-eyed Susan with care and mindfulness. This plant can take over or become invasive within your garden or landscape.
Many gardeners who work with black-eyed Susan will dedicate a flower bed just for this plant—allowing for easy removal of seedlings outside the designated area.
Does Black-Eyed Susan Have Invasive Roots?
Black-eyed Susan has roots that grow horizontally and typically remain in the top 24 inches of soil. This plant gets all the nutrients it needs to thrive from the shallow layers of soil, which is why the roots do not go deeper.
The roots of black-eyed Susan are not considered invasive. Their roots are not strong or deep enough to disrupt structures around them, like fences, driveways, or other foundations.
Furthermore, the roots of this plant are not the main culprit for its ability to spread. Black-eyed Susan spreads rapidly due to the seeds it produces and the underground stems.
We will discuss the spread of black-eyed Susan in more detail.
How Does Black-Eyed Susan Spread?
Black-eyed Susan has the potential to spread aggressively if given a chance. Once planted, this flower will begin to root and spread underground stems called rhizomes.
These rhizomes will produce new shoots and appear to be a new plant. However, this will just be an extension of your original flower.
Additionally, black-eyed Susan is self-seeding. They will produce flowers and seeds the same summer they are planted. The following Spring, those seeds will germinate, and the black-eyed Susan will continue to grow.
How Do You Keep Black-Eyed Susan From Spreading?
You can both enjoy black-eyed Susan in your landscape and keep them from spreading out of control. Limiting the spread is especially important if you have other plants nearby.
Too much spreading can cause black-eyed Susan to choke out the surrounding plants, eventually killing them. To stop the spread, the first step you can take is to remove flower heads before they drop seeds.
You can remove the blooms after they start to fade and before they dry up. Additionally, deadheading your plant will encourage new growth and a fuller-looking plant.
Another step you can take to limit the spread of this flower is removing clumps of the plant, including the rhizomes. Ensure you remove the entire piece of root when doing this, as anything left behind can produce another plant.
Learn more on our blog post, "Does Black-Eyed Susan Spread? [And How To Prevent This]."
Where Is The Best Place To Plant Black-Eyed Susan?
When managed correctly and cared for, black-eyed Susans bring warm yellow blooms to your garden. You can plant these flowers along a walkway, garden bed, or in more confined spaces like a hanging basket.
You start planting black-eyed Susan when soil temperatures are 70–75 degrees. Pick an area of your garden that gets full or partial sun. These flowers bloom more consistently when receiving adequate sunshine.
Check the surroundings before you plant. Black-eyed Susan should be planted far enough from other plants to reduce the risk of this flower taking over or stealing nutrients from them.
This flower is hardy and can survive in varying conditions. However, they thrive best in fertile, well-draining environments.
You can plant black-eyed Susan indoors if the outside conditions aren't optimal. Simply sprinkle seeds over seed starting mix in a pot. Keep the seeds uncovered, as they need plenty of sunlight to germinate.
Read more on our blog post, "How and When To Transplant Black-Eyed Susans."
How Much Space Does Black-Eyed Susan Need?
A single black-eyed Susan plant can spread 12–18 inches wide and reach 4–6 feet tall. This mature size changes slightly based on which species of black-eyed Susan you plant.
When spacing, consider the mature size of this plant. You may have to do some additional research for your specific species.
To create a border and give your plant optimal space, they can be planted one foot or more apart. However, you can plant seeds closer together to limit their spread.
Is Black-Eyed Susan A Low-Maintenance Plant?
Black-eyed Susan is a low-maintenance plant and easy to grow. Establishing plants require plenty of sunlight, but they can survive through periods of drought and are hardy in a variety of soils.
One part of maintaining black-eyed Susan includes deadheading and pruning. This should be done once a year, or more, to control any unwanted spreading.
Furthermore, you can fertilize once at the start of each growing season, but this is not always necessary.
Does Black-Eyed Susan Come Back Every Year?
Certain species of black-eyed Susan are perennials, and others are annual plants. The annual species do self-seed. This means the original plant will not survive, but the seeds it drops may continue the cycle with new plants in the Spring.
Perennial species of black-eyed Susan include sweet black-eyed Susan (Rudbeckia subtomentosa) and cultivar Goldstrum (Rudbeckia fulgida). These species will come back year after year, though their blooms may be slightly different each year.
In either case, you can expect black-eyed Susan to come back yearly. Whether it is the original plant or newly germinated seeds.
How Can You Get Rid Of Black-Eyed Susan?
If you are trying to get rid of black-eyed Susan in your garden, you might have found this difficult. Thankfully, there are ways to eradicate this flower from your landscape.
You must be vigilant to get rid of back-eyed Susan, which requires a three-step process. Begin by cutting the plants down to ground level at the end of the growing season. Cut the plants back using gardening sheers.
Cut your flowers down before they drop new seeds.
Next, use a shovel to dig out the roots of your black-eyed Susan. All roots and rhizomes need to be removed to stop any new plants from growing.
Additionally, you can dig up a little extra soil to ensure you are removing any pieces of root left behind.
After removing your plants and roots, the second step is to lay down herbicide.
The herbicide of your choice should only be applied to the area your black-eyed Susan was planted. Avoid getting the solution on neighboring plants, as this will kill them.
The last step in removing black-eyed Susan entirely is to till the soil. Use your till to turn up the top 6–10 inches of soil where your plant once was.
Tilling will further reduce the chances of your black-eyed Susan returning, preventing other weeds from appearing. Furthermore, tilling will aerate the soil and prepare it for new crops.
Monitor the area for any new sprouts of black-eyed Susan in the following growing season. If new plants do appear, you will have to repeat this process.
Black-eyed Susan technically is not an invasive plant. However, this plant spreads rapidly, creating an invasive feel in your landscape. We hope you found this article insightful when it comes to caring for your flowers.
Are you looking for more information about caring for black-eyed Susan? Have a look through our blog post,