Black Eyed Susan is a common name for many different flowers. They all look similar, but Rudbeckia Hirta, Rudbeckia Fulgida, Rudbeckia Triloba, are all quite different! So, in this article I will cover how to grow Black Eyed Susans as well as some of the key differences between the species.
How to Grow Black-Eyed Susan
In a nutshell, all varieties of Black-Eyed Susan/Rudbeckia need the following to grow and thrive;
- Full sun, 6 hrs direct sunlight per day
- Well drained soil
- 2′ Spacing
- Can grow in almost any soil
- True Natives will be tough, drought resistant, pest and disease resistant
- Specialized hybrids may need extra care
- Rabbits do enjoy nibbling on young plants / early Spring growth
Black-Eyed Susan General Characteristics and Facts
Although known by many different names depending on what region you are in, Black-Eyed Susan is generally a ‘catch-all’ term to describe the many different species and varieties of Rudbeckia. Variations of Black-Eyed Susan / Rudbeckia abound in gardens and meadows across the United States.
Blooming from June-Sep depending on the variety, these native perennials are an excellent choice for any garden. With so many different varieties available, we will focus in on some of the more common varieties you’ve probably seen in flower beds or in the wild.
The main varieties of Rudbeckia / Black-eyed Susan all bloom for long periods of time for a perennial. Typically a month or more. Their bright yellow flowers add a great accent to any garden as a background flower or a center display.
Since these plants are native to a large portion of North America (Midwest, Southeast, Mid-Atlantic, New England – basically everywhere but the desert), they are resistant to many diseases and damaging insects.
How Rudbeckia benefits your local ecosystem
This plant attracts a variety of pollinators, namely bees and butterflies. It is the larval host to two different species of butterfly, the Bordered Patch and the Gorgone Checkerspot. Leaving the blooms to form seeds will allow the plant to self-seed, as well as attract birds who enjoy the seeds. This makes the plant interesting to watch even into the fall, as you may notice a stem suddenly begin swaying on a calm day, only to discover a small wren or other bird sitting on the seed head having a snack!
Remember, this is a prairie plant! Black-Eyed Susans will need full sun in order to reach its full height potential. It readily grows in the wild, and competes well with other plants. So, that means you can enjoy varieties of black-eyed susans together to create a stunning yellow display that is long lasting.
The perennial black-eyed Susan, Rudbeckia Fulgida is widely available for purchase in garden centers across the United States, and is the most common variety seen in residential/commercial gardens. With hundreds of special variations to choose from. Although the most economical way to enjoy this plant is to either purchase seeds at any store that sells gardening supplies, or collect them from the wild after the blooms have dried, but before the birds have eaten them…….
Growing Conditions for Rudbeckia
Black-eyed Susans are very rugged/tough, and can tolerate almost any soil, be it clay/sand/loam. All Rudbeckia prefer full sun, so keep that in consideration. It is possible to grow in partial shade, but the plants will not get as large, nor produce as many blooms. I’ve successfully grown them multiple times over the years in heavy clay. Although it prefers medium-moisture soil, it is drought tolerant.
But, don’t forget to use your own common sense – if during the peak heat of summer there is no rain for a week, and the leaves are starting to get crisp on the edge, then the plant needs water. However, as far as most perennial flowers go, this is one of the lowest maintenance plants you could have in your garden.
As with most flowers, if you clip off flower heads after they have bloomed, it generally will encourage the plant to form more blooms. This is known as ‘dead-heading’ your plant. It is common practice for many gardeners looking to prolong the bloom period of their perennials.
So, if you are considering purchasing some Rudbeckia, or growing some from seed, please use the reference table below. The sizes and spacing listed are reference for typical growing conditions (full sun/med water). If the plant is grown in fertile soil, fertilized, and tended to then you might have your plant exceed the height and spacing. Conversely, if the conditions aren’t perfect for the plant, then the plant might only grow on the low end of the size/spacing ranges listed.
Rudbeckia Growing Reference Table
|Common Name||Perennial black-eyed Susan||Sweet Black-eyed Susan||Black-eyed Susan||Brown-eyed Susan|
|Species Name||Rudbeckia Fulgida||Rudbeckia Subtomentosa||Rudbeckia Hirta||Rudbeckia Triloba|
|USDA Garden Zone||3-9||3-8||3-9||3-9|
|Sunlight req||Full Sun||Full Sun||Full Sun||Full Sun|
|Moisture req||Dry-Medium – Well Drained||Dry-Medium – Well Drained||Dry-Medium – Well Drained||Dry-Moist – Well Drained|
|Height||3 ft (1m)||3-5 ft (1-1.5m)||1-3 ft (30 – 100 cm)||3-6 ft (1-2m)|
|Spacing||1-2 ft (30-60 cm)||1-2 ft (30-60 cm)||1-2 ft (30-60 cm)||3-4 ft (1-1.3m)|
|Bloom Size||3-4″, 7-10cm||3-6″, 7-12cm||2-4″ 5-10cm||1-3″, 2-7cm|
|Characteristics||Multiple Stems w/ single bloom||Multiple Stems w/ Single bloom||Multiple Stems w/ single bloom||Shrub like, many stems with many blooms|
|Seed Planting Depth||Surface Sow||Surface Sow||Surface Sow||Surface Sow|
|Startification Required?||Yes, 30 days||Yes, 30 days||Yes, 30 days||Yes, 30 days|
|Bloom Time||Mid-late summer||Late Summer||Summer||Late Spring-Late Summer|
Grow Black-eyed Susan from Seed and Save some money $$$!!!
I recommend growing this plant from seed, as it is the most economical way to obtain a large number of healthy plants, and be sure of exactly what species they are. To do this, you just need to purchase from seed from a trusted source. I’m a big fan of the following companies, and have used their seed for years. Everwilde seed comes in nice resealable packets, and have good germination rates. Prairie Moon Nursery have great seeds, and a ton of excellent instruction for stratification.
You really should check out our guide on saving Black Eyed Susan Seeds. It is a step by step process that shows you how to save large quantities of seed without any chaff!
Or save your own Rudbeckia seed to really save some money
Of course, you could collect your own seed from plants you see growing in the wild. I’ve done this many times. It is a pretty smart thing to do actually. If the plant is truly a local eco-type, then you know that it is perfectly adapted to survive in your local area. That doesn’t just mean the climate – it means resistance to disease and pests/insects. So, you know you would be getting a hardy plant. If you start your seeds early enough, you should be able to get blooms the first year. Otherwise you will likely need to wait until the second year.
Growing Black-Eyed Susans from seed
Want to to learn how to germinate all types of Rudbeckia / Black-Eyed Susan seeds? Then click below to check out our detailed guide on germinating Black-Eyed Susans!
In general, the easiest way to plant this seed is to plant them in starter pots during the winter, and set them outside for winter sowing. Here is the seed starter trays I recommend: LARGE SEED STARTER TRAYS . But, you can plant them in early spring. These seeds germinate best when just pressed into the soil, not covered up. They need to be kept moist, not wet. You can expect germination in a roughly 2-4 weeks once the temperatures warm up. I would recommend to let them grow in larger pots, 4” (10cm) deep/wide or more, until they reach a large size before transplanting into the ground. Click here for additional SEED STARTER TRAYS. Then make sure you protect them from rabbits/deer, as they often will eat young plants. I recommend using Liquid Fence Concentrate to keep rabbits & deer away. It is not harmful to the animals, but gives them a smell & taste deterrent to keep them away from your plants.
Typical Garden Uses for different varieties of Black-Eyed Susan
Each variety I have described in this article has it’s own special uses. But, in general all varieties of Black-Eyed Susan are quite versatile. These plants bloom for such a long time that you really should have at least a few in your flower beds or yard.
Perennial Black-eyed Susan / Rudbeckia Fulgida
This variety might self seed somewhat, so come spring you may have some volunteers! I just transplant to other areas to fill in gaps, or give you neighbors/friends. But this plant is hardy, and this specific species, or the popular ‘Goldstrum’ variety is what you picture when you think of this plant. This variety of Rudbeckia will get up to 3′ in good conditions with full sun. It will bloom for a long time, and should be given a prominent place in any garden. This variety can do great in a common mulched flower bed, as it won’t self-seed that much. So it is well behaved, decent sized, but yet it still keeps to itself as it will not get very ‘leggy’.
Rudbeckia Fulgida is often available in garden centers across the country. If you have seen Black-eyed Susans around your neighborhood, it is likely this one – most likely the Goldstrum type. It is a best seller for a reason. As this plant has all of the rugged, tough characteristics that all Rudbeckia’s have, but this is probably the most showy. If your flower beds typically have plants spaced out, with mulch in-between each plant than this is your best choice that will suit your needs.
Sweet Black-eyed Susan / Rudbeckia Subtomentosa
This variety can get very tall. I’ve grown several that were more than 6’ (2m). As far as tall plants go, it is a very hardy plant, good for the ‘back’ of the garden. I’ve grown these several times, and was always impressed with how full they got, and how prominent the blooms were rising above my other Rudbeckia. This variety is really fun to let the flower heads stay on, long after the bloom so that seed develops. Once that happens, you get treated to seeing songbirds landing on the seed-heads to pick out seed. Since Sweet Black-Eyed Susan is so tall, you really get to see it sway more when a bird lands on it.
Although this variety is normally not available in garden centers, or seed racks in the store, I’ve found them on Amazon at the link below. I’ve purchased many seeds from Everwilde in the past and have had good luck with them. The price was $2.50 before shipping, but this might change so check the price at the link below;
Black-eyed Susan (biennial or perennial) / Rudbeckia Hirta
This is the species that you commonly see growing along roadsides or in pastures as you drive through the countryside. It is very short lived, but will self seed. This version shouldn’t become invasive in a well managed garden. It can make a great accent or background within a larger garden. I have several of these dispersed throughout my ‘meadow’ garden, as they provide nice color and fullness to the overall meadow. This can make a great border to a wooded area, that will self-seed and replant itself every year. As with the other Rudbeckias, birds will visit these seed-heads for months to come.
Brown-eyed Susan / Rudbeckia Triloba
This species of black-eyed susan can be the ‘biggest kid on the block’ when it comes to Rudbeckia. I’ve personally grown a specimen that was over 8’ tall (2.5m). That was when I learned that Rudbeckia generally doesn’t need fertilizer…..
In my experience it also blooms for the longest duration, starting in late June and lasting through August into September. But, I’ve never had them live very long, so the excess number of blooms makes sense. This has the smallest bloom size, but it compensates for this by making the most blooms, by far.
This plant can be aggressive, and will self seed profusely. I recommend this species in a more isolated location, or among other thick/tough plants. I’m currently growing one brown-eyed susan in an isolated location surrounded by lawn and small evergreen shrubs. I’m doing this to make ‘offspring’ control easier. In this way, seeds shouldn’t germinate in the evergreen shrub (no sunlight), and any seedlings within my lawn can be handled by a lawnmower.
I’ve seen this in the wild several times, and it has never been nearly as large as when I grew it in a more well-tended, mulched garden. I’m thinking this is do to two reasons. First, the species in the wild had lots of competition, as it was in a meadow/prairie. Second, some of the plants were getting full sun, but not 12 hour sun. More like 8 hours, so the reduced sunlight helped keep their size down (I think).
Other notes on growing Black-Eyed Susan
So, which varieties will you choose? It depends on your situation, and what you think you want, or will want in the future. I always say that you should think 3 years into the future when designing your garden. It is always very easy, but expensive to just run down to your local garden center or big-box store and pick up a few plants. They typically run from $5-$12 dollars depending on the size or variety. However, most of these will be specific hybrids or cultivars. This distinction is important if you wish to propagate this plant further from seed. The seeds from hybrids will not produce plants that are like the original hybrid (plant you got the seeds from). This is because by definition, a hybrid is when two different plants are pollinated to produce a new species, offspring. If you purchase a cultivar, then you can use the seeds to grow more of the same plant.
Frequently Asked Questions about Black-Eyed Susans
Can Rudbeckia grow in clay soil?
Yes. No problem growing in clay soil as long as it drains well. This plant is what I like to call a clay-buster plant. In fact, I’ve only grown them in clay, since every home I’ve lived in has been blessed with clay soil……blessed. Yeah – that’s the ticket.
Can Rudbeckia grow in shade?
Well, not really. Even if it can survive, it probably won’t be attractive to you or the wildlife that would normally visit it. I’ve seen them growing in partial shade, but these weren’t large attractive plants. The plants I observed definitely didn’t appear to be reaching their full potential. So I wouldn’t suggest that you try anything but full sun. If the plant has evolved to grow best in full sun, then you should grow it in full sun. Fighting with mother-nature normally doesn’t pay off well.
Can I, or When should I divide Rudbeckia?
You can divide Rudbeckia every several years. Alternatively, if you notice your Rudbeckia is ‘dead’ or not growing in the center, then the following Spring it should be divided. It can be divided in Spring or Fall, before top growth really begins. Just dig it up, and use a shovel to separate the plant. Then rebury the sections, and it should grow as normal.
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