The Brown-Eyed Susan (Rudbeckia Triloba) Care Guide

The Brown-Eyed Susan, otherwise known as the Rudbeckia Triloba, Black-Eyed Susan, Native Black-Eyed Susan, Thin-Leaved Rudbeckia, Thin-Leaf Coneflower or Branched Coneflower, is a very popular perennial plant native to the Rocky Mountains, Northeast, Southeast, and the Southwest of the United States.

Best known for its low maintenance and fast growth, this perennial will likely liven up your house (or garden) with its dark green colored leaves. But, only if you learn how to take proper care of it for it to thrive.

Fortunately, taking care of your Black-Eyed Susan is not too difficult – as long as you follow our guidelines in this Black-Eyed Susan Care Guide. Now let’s get started.

The basic care guidelines you need to remember for your Black-Eyed Susan are the following:

  • Water: The Black-Eyed Susan requires moist yet porous soil.
  • Light: Keep your Rudbeckia Triloba in an environment where it can receive full sun on a daily basis. 
  • Soil: Make sure to keep the Black-Eyed Susan in soil with moist but well-draining properties, so ideally, one that is made of loam and clay.

And that’s practically it! If you keep these three factors in check, your Black-Eyed Susan will likely have all it needs for it to survive and even thrive.

Scientific / Botanical Aspects

In botanical terms, the Black-Eyed Susan belongs to the Asteraceae family, the genus Rudbeckia and the species Triloba, hence its scientific (or botanical) name Rudbeckia Triloba.

As with other Rudbeckia’s, the Black-Eyed Susan is a herbaceous plant, which means it will die back to the ground every year. 

Growing Region

The Black-Eyed Susan is a plant native to the Central and Eastern United States. This is why the Rudbeckia Triloba is used to growing in specific regions such as the states in Rocky Mountains, Northeast, Southeast, and the Southwest of the United States.

As a rule of thumb, we recommend to always keep in mind your plants’ native region and environment, since these are the conditions that your Black-Eyed Susan is most accustomed to, thus where it can most favorably.

With this in mind, the Rudbeckia Triloba will be most used to the heat zones in the 1 – 12 region, as the plant hardiness level falls between 4a, 4b, 5b, 5a, 6a, 6b, 7a, 7b, 8b, 8a and the ideal climate zone is between 1, 1A, 1B, 2, 2A, 2B, 3, 3A, 3B, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24.

Growth and Size


In terms of size and growth, the Black-Eyed Susan is a relatively fast grower, which makes things tricky for any plant enthusiast.


But what exactly does this mean for your Black-Eyed Susan? How large a pot should you consider, how tall, how wide can it get? Let’s jump in…

The Rudbeckia Triloba can grow up to 2′ – 3′ (60cm – 90cm) in 2′ – 3′ (60cm – 90cm) and 1′ – 2′ (30cm – 60cm) in 1′ – 2′ (30cm – 60cm). 

These dimensions make the Black-Eyed Susan a relatively medium perennial compared to others, so it’s best to keep this fact in mind since it will affect where you want to keep yours at home.

This is why experts recommend keeping an area of approximately 18″ (45cm) free so the Black-Eyed Susan can spread to its best extent.


In terms of watering, the Black-Eyed Susan is a fairly complicated plant to take care of. This is mostly because it has a not so straightforward watering schedule and somewhat irregular watering needs.

Specifically, most experts agree that the Rudbeckia Triloba requires moist yet porous soil. Which is why it is considered a plant with relatively average needs in terms of water. 

As a rule of thumb, you should remember to keep your Black-Eyed Susan in soil with moist but well-draining characteristics, as these will guarantee the right conditions for your plant to grow and thrive. 

When you consider this, this is why you should aim to choose soil that has good drainage, moist, and occasionally dry properties to keep the right moisture levels at all times. 

In our experience, the famous ‘thumb’ or ‘finger’ test is what works best for the Black-Eyed Susan since with it, you will be able to give it the right amount of water, every time – regardless of the environment or placement where you do decide to keep it.

Soil Mix

As mentioned earlier, the Black-Eyed Susan prefers to have soil with good drainage, moist, and occasionally dry properties, reason why you need to make the soil mix out of loam and clay.

This is why most experts agree that the Black-Eyed Susan requires soil with clay, high organic matter, and loam (silt), which will give you the right conditions it needs.

In addition to this, expert gardeners recommend having preferably alkaline, acid or neutral soil.

Light and Placement

In terms of light & exposure, the Black-Eyed Susan requires full sun in order for it to thrive under the right conditions. 

Most experts agree that this perennial will do well as long as you keep it in full sun, and it will be able to grow properly.

Specifically, we recommend that you place your Rudbeckia Triloba in little to partial shade (only 2-6 hours of direct sunlight a day), to full and direct sun (more 6 hours of direct sunlight per day).


Being a herbaceous plant, the Black-Eyed Susan will die back to the ground every year. But, you can expect it to have its ‘prime-time’ during the summer (mid, late), and during the fall.


You can expect your Black-Eyed Susan to flower around the summer and in the fall months from July to September (summer), and from October to December (fall).

In particular, this perennial is well known for its long bloom season, flowers for cutting and showy flowers around the plant enthusiast community.

The Black-Eyed Susan produces some beautiful yellow, or brown/copper, black and gold/yellow flowers around this time of year.


The leaves from the Black-Eyed Susan have a beautiful dark green color during most of the year.

In particular, they have an alternate organization in its leaves. You can expect the leaves from your Rudbeckia Triloba to be around (3-6 inches) in size.

Attracts, Tolerance and Resistance

The Black-Eyed Susan is well known for being able to attract butterflies, so keep that in mind when choosing your plant, as you’ll likely end up finding one or another in your garden.

Additionally, it has a special tolerance for drought and animals like deer, so don’t worry if any of these come along, your Rudbeckia Triloba will be fine.


Does your Black-Eyed Susan have any garden recommendations? Does it serve any gardening purposes? Here’s how you can get the most out of your new plant.

Most Rudbeckia Triloba owners agree that this perennial will look great in most cottage and rustic gardens of all types. Other owners consider that they compliment well most gardens of informal and cottage, and in prairie and meadow styles. 

In particular, the Black-Eyed Susan’s best location within your garden is in beds and borders, others use it for landscaping in a mass planting, border, cutting garden, or a woodland garden.


Even though we covered a lot of care information for your Black-Eyed Susan, remember the basics: sunlight, soil and water, as these should be enough to grow a healthy plant at home.

Martin Duran

Hey y'all! My name is Martin Duran and I am from Cali, Colombia. Since 2018 I have been learning about plants and how to take care of them. Here's is my journey... “The clearest way into the Universe is through a forest wilderness.” ― John Muir

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