How to Grow Black-eyed Susans: The Complete Black-eyed Susan Flower Guide

Black-eyed Susans (Rudbeckia hirta)in a field

Black-eyed Susans (Rudbeckia)

Photo Credit
Flower_Garden/Shutterstock
Botanical Name
Rudbeckia hirta and other species
Plant Type
Flower
Sun Exposure
Full Sun
Part Sun
Bloom Time
Summer
Fall
Flower Color
Orange
Red
Yellow
Hardiness Zone
3
4
5
6
7
8
9
Special Features
Attracts Butterflies

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Planting, Growing, and Caring for Black-eyed Susans

Catherine Boeckmann

Beloved by pollinators, black-eyed Susans (Rudbeckia hirta) generally bloom from June to August, often blanketing open fields with their golden-yellow beauty. Learn how to care for this native wildflower, when to cut it back, and how to save seeds for replanting.

What Are Black-eyed Susans?

The “black eye” of black-eyed Susans refers to the dark brown center of its daisy-like flower head. A member of the aster family, Asteraceae, and native to eastern North America, it has become naturalized in Zones 3 to 9. And while some species of black-eyed Susans have additional names—such as Gloriosa daisies—they all belong to the Rudbeckia genus.

Black-eyed Susans grow 1 to 3 feet tall or more with leaves of 6 inches, stalks over 8 inches long, and flowers with a diameter of 2 to 3 inches. Butterflies, bees, and other insects are attracted to the flowers for the nectar. As they drink the nectar, they move pollen from one plant to another, causing it to grow seeds that can move about easily with the wind. Learn more about our favorite wildflowers.

“The Silvery Checkerspot butterfly uses Rudbeckia species as a host plant,” explains the “Seed is consumed by song birds, especially goldfinches.”

In the garden, they do well in landscapes, borders, butterfly gardens, or containers. Also, they are outstanding cut flowers.

Black-eyed susans are Sun worshipers who forgive neglect and are tough as nails. However, avoid overcrowding these plants or watering their leaves (vs. soil level), which can lead to fungal disease.

Note that varieties can be annual, biennial, or perennial. The popular Rudbeckia hirta is treated as a short-lived perennial. See more about the recommended varieties below.

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Planting

The black-eyed Susan thrives in full sunshine. It tolerates partial sun, but it will not bloom as reliably. It’s best if the soil is fertile (not poor), though this plant can tolerate tough conditions.

When to Plant Black-eyed Susan

  • Set new plants out in the spring after all danger has passed or plant in the fall. The optimal soil temperature for germination is 70° to 75° F. Do not plant in the hot summer.
  • If planting by seed, sow seeds about 6 weeks before the average last frost.

How to Plant Black-eyed Susan

  • Plants should be set 18 inches apart. Remove weeds and loosen the soil. Make a hole a few inches wider than the plant and set it in the hole; backfill it with soil, tamp gently, and water it well.
  • If planting from seed indoors, sprinkle seeds on top of the regular seed starting mix. Do not cover the seed, as they need light to germinate. Plant your seedlings outdoors after any danger of frost has passed. Since black-eyed Susans can spread between 12 to 18 inches, plant seeds closer to prevent lots of spreading, or plant further apart to make a nice border and to prevent the spread of disease.
  • Black-eyed Susan spreads by self-seeding (after the first year) and underground rhizomes; this can result in it overtaking other nearby flowers.

Growing

  • Check plants regularly to see if they need watering. Avoid letting them dry out, and avoid excess moisture on the leaves, as this can encourage disease. (Provide plants with proper spacing.)
  • Deadhead the flowers any time of year (remove the faded/dead flowers) to prolong blooming and minimize self-seeding.
  • Remove dead plant material in the spring to reduce the risk of infection.
  • Divide perennial types every 3 to 4 years to ensure healthy plants and prevent excessive spreading.

Should You Cut Back Black-Eyed Susans

When it comes to black-eyed susans, we prefer to delay cutting back until spring. 

  • This plant is a favorite with wildlife, native insects, and birds with its dried seeds. 
  • In addition, overwintering birds find protection in plant stubs and ground covers.
  • Plus, the mound of foliage will insulate the roots and protect the plant over winter. 

However, black-eyed Susans are a big reseeder. To avoid this, cut the spent flowers back just below the mound of foliage.

Types

As well as the traditional black-eyed Susans, which grow 1 to 3 feet tall (or more), there are dwarf varieties that reach no more than 1 foot (perfect for containers). Varieties can be annual, biennial, or perennial.

The popular roadside Rudbeckia hirta with showy yellow flowers is a biennial in the wild but treated as a short-lived perennial in the garden. It self-seeds abundantly, naturalizing easily. If you sow seeds 6 weeks before the last frost date, you’ll see flowers in the first year, and they may return a few more seasons (but you can’t always count on it). Some of its many hybrids include:

  • ‘Autumn Colors’: yellow, orange, red, and brown flowers; 18- to 24-inch stems
  • ‘Becky Mixed’: lemon-yellow, golden-yellow, dark red, and reddish-brown flowers; 10- to 16-inch stems
  • ‘Prairie Sun’: All-America Selections winner; 4- to 6-inch bright orange flowers that fade to yellow at the tips; 28- to 23-inch stems. !
  • ‘SDzԴǰ’: large golden flowers with big, chocolate-brown centers; 12- to 16-inch stems
  • ‘Toto Gold’: dwarf type; classic yellow flowers with black centers; 12- to 16-inch stems; ideal for containers

There are also true, long-lasting perennials that will keep coming back and blooming year after year.

  • ‘GDZٳܰ’ black-eyed Susans (Rudbeckia fulgida ‘Goldstrum’), known for its longevity and a regular plant in late summer and fall gardens
  • ‘Sɱ’ black-eyed Susans (Rudbeckia subtomentosa), bearing taller flowers and ideal for more naturalized garden or meadow
  • ’Gloriosa Daisies’ (Rudbeckia hirta ‘Gloriosa’), 12- to 36-inches tall and tolerates partial shade; giant, bi-color double flowers.

Finally, some Rudbeckia varieties are annuals, such as the Clasping Sunflower (Rudbeckia amplexicaulis), a low-growing plant for the front of a border garden.

Harvesting

Cut flowers for display just before buds completely open. Use large blooms as centerpieces and smaller ones as accents. Change the water every day to keep them fresh. Vase life is 8 to 10 days.

How to Collect Seeds of a Black-eyed Susan

Once the seed heads are dry and brown, it’s time to clip some stems. Pop off the seed heads from the stems and toss them in a small jar; close the lid and shake it to loosen the seedheads. Then, dump the seed heads from the jar into a sieve with a white piece of paper below it. Break up the seed heads in the sieve with your fingers. The seeds will come off and fall through the sieve onto the paper! Fold the paper in half and carefully funnel those seeds into a paper envelope. Close and label the envelope and store it in a cool, dry place. 

Learn more about how to save seeds for next year.

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Wit and Wisdom

  • Black-eyed Susans are meant to symbolize justice. Find out more flower meanings here.
  • The genus name Rudbeckia honors Swedish scientists Olaus Rudbeck (1630–1702) and his son, Olof Rudbeck (1660–1740).
  • The species name hirta means “hairy” and refers to the short bristles that cover the leaves.
  • Black-eyed Susans are the state flower of Maryland.

Pests/Diseases

Black-eyed Susans are deer-resistant plants.
Diseases: powdery mildew, aster yellows, Botrytis blight, southern blight, angular leaf spot, fungal leaf spot, downy mildew, rust, white smut, Verticillium wilt.
Pests: aphids, nematodes, slugs, and snails

Flowers
About The Author

Catherine Boeckmann

Catherine Boeckmann loves nature, stargazing, and gardening so it’s not surprising that she and The Old Farmer’s found each other. She leads digital content for the website, and is also a certified master gardener in the state of Indiana. Read More from Catherine Boeckmann
 

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Comments

Glenna Evilsizer (not verified)

4 years 1 month ago

While at a home supply store about a year ago looking for a product to repel deer (north/mid Michigan) the garden supply agent told me while the sprays work fairly well he had another good idea and took me to the closet supply area and gave me a box of moth balls. He told me to throw a few around the flower bed every few weeks/months and it should help to deter the deer. The deer had eaten all of my new tulips that spring and I was heart broken. Anyway, I was willing to try the moth balls and it DID work. I have the rare occasional deer foot print in the flower bed but no new chewing damage noticed. Just want to share. Mind you, I do not have any pets that are allowed into that area nor do I have any small children in my home or my neighbors. So its a win/win for me.

Rick Rios (not verified)

4 years 1 month ago

I have very healthy growing forest of black eyed susans. I do not mind them leaching out into other areas. What end of season care should I take to best winterize them. Do I leave them alone, trim them or cut them to the ground? Vancouver Washington, USA

Hi Rick, Black-eyed susans are one of those perennials that you can simply leave alone through the fall for winter interest and for the birds to enjoy. 

However, if you don’t want to leave it, cut back the perennial to two inches above the ground.

See more about cutting back perennials.

James ODonnell (not verified)

4 years 2 months ago

when to transplant plants or is it best to sow seeds. Have a friend that wants these flowers.
the ones that we have see to be taking over and even jumped the sidewalk to get into another flower bed

We would either plant small transplants in the fall or we’d start seeds indoors about 4 to 6 weeks before the last spring frost date.  The flowers seem to handle transplanting well enough from seedling, and tend to bloom stronger and healthier than directly-sown seeds.  If you sow inside, ensure the seeds aren’t covered too heavily with soil. Again, they need the light to germinate. Keep seeds and seeding moist, but not soggy.

You can certaily sow seeds, too, and these flowers self-sow so they pick up from seed pretty easily. Just note that it could take a year for the seed to bloom so this requires more patience. To sow: Sprinkle the seeds on top of regular seed starting mix about six weeks before the last frost date. Do not cover the seed as they need light to germinate. Plant your seedlings outdoors after any danger of frost has passed.

Diep (not verified)

4 years 3 months ago

Hi,

Deers and rabbits love munching on my flowers. I use two products that seem work very well. One is deers and rabbits repellent spray. But it smells very strongly bad. The second one is hot pepper spray. I made it from boiling the seeds of Thai red chillies. I sprayed on my garden. They ate one and didnt come back for 3 years. They came back this year and I sprayed the pepper liquid again and it seems like they havent come back. Hope it helps.

Claudio J Amaral (not verified)

4 years 4 months ago

its a losing battle every year. I spray, spray and spray but they always eat the buds a few days before blooms.

Penny (not verified)

4 years 4 months ago

I moved and replanted a black eyed susan about 5 years ago and where I put it it seems to have put out runners and now it is taking over my landscaping. How do I get rid of the runners and just keep the main plant. The previous spot was bound by sidewalk and stayed in the original spot.

Black-eyed Susans can spread via seeds and underground rhizomes. To prevent spreading, deadhead the flowers before they set seed. As to controlling the spreading of rhizomes, that is more difficult. As you may have found, if you don’t get every piece, chances are that section of rhizome (a modified stem) that is left will produce another plant. Here are suggestions from the Purdue Cooperative Extension as to how to combat this problem:
1) Provide a large area of mulch around the mother plant. Keep up with digging up any rhizomes that spread from that mother plant (several times each growing season).
2) Another option would be to replant the mother plant in a container (with drainage holes) and put the container in the ground, with the rim about 2 inches above the soil surface. Check periodically to make sure rhizomes do not escape the container. Every year or two, prune the roots to keep the plant confined in its container, or repot as needed.
3) A third option would be to insert a barrier (or collar) around the plant, such as a section of deep-walled bottomless pipe about 8 to 18 inches deep, to prevent rhizomes from spreading.
In the meantime, use a garden fork to expose current rhizomes and then gently remove them from the soil.

Hope this helps!

Wayne P Petry (not verified)

4 years 4 months ago

So beyond the fact that Black-eyed Susans are nice to look at, Black-eyed Susan has been known to cause mild poisoning in cattle and pigs. It may also be dangerous to cats, dogs and other household pets. This flower should also be kept away from small children, who may chew it or get the sap on their skin.they are poisonous to most