Why are my Black Eyed Susans leaves turning black?

Asked By: Willa Acedo | Last Updated: 17th June, 2020
Category: food and drink vegetarian diets
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Black spots on Rudbeckia, also known as black eyed Susan, are very common and occur in a large percentage of the population each year. There are many causes, but the most common by far is the fungal disease called Septoria leaf spot, a common disease of tomatoes. Black spots on Rudbeckia don't interfere with blooming.

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Herein, how do you treat Black Eyed Susan fungus?

Control Powdery Mildew, Leaf Spot and Rust

  1. Add 1 gallon of soft water into a bucket.
  2. Transfer the diluted neem oil to a clean handheld sprayer or pump sprayer.
  3. Reduce the treatments to a 14-day schedule to prevent the disease from returning.

Secondly, what do you do with Black Eyed Susans at the end of the season? You can cut back this plant about halfway or more once it has finished blooming, removing spent flower stalks, and a second bloom might occur in late fall. In fall, you can cut this perennial back to 2 inches above the soil line if the plant is diseased or you consider the dead stems unattractive.

Just so, what does Black Eyed Susan leaves look like?

The leaves of the black-eyed susan are quite long, measuring approximately 5-17.5 cm. They are thin and lanceolate-to-ovate in shape. The leaves have winged petioles, are prominently veined, rough to the touch, and sometimes sparsely toothed. Leaves are several and grow irregularly along the length of the stalk.

Do Black Eyed Susans need a lot of sun?

Black-eyed Susans thrive in full sun and well-drained soil and have high tolerance to soil salt. Less sun translates to smaller and fewer flowers. Though drought is tolerated, consistently moist soil helps plants naturalize readily.

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Do Black Eyed Susans spread?

It's best if soil is fertile (not poor) though they can tolerate tough conditions. Black-eyed Susans generally grow between 1 and 3 feet tall (though they can grow taller) and can spread between 12 to 18 inches, so plant seeds closer to prevent lots of spreading or plant further apart to make a nice border.

What is wrong with my black eyed Susans?

Black spots on Rudbeckia, also known as black eyed Susan, are very common and occur in a large percentage of the population each year. There are many causes, but the most common by far is the fungal disease called Septoria leaf spot, a common disease of tomatoes. Black spots on Rudbeckia don't interfere with blooming.

Do Black Eyed Susans need a lot of water?

Black-eyed Susans do not need much extra water once they're comfy and established in the garden. You do need to water them when you first plant them, though, to help the plants grow new roots and settle in. Water well whenever the top inch of soil around the plants is dry.

What is killing my black eyed Susans?

Insect Pests
As with many other types of garden plants and flowering perennials, aphids are the primary insect pest of black-eyed Susans. Goldenglow sawfly is a more serious pest, whose striped gray larvae can completely strip leaves from plants. Sevin or the insecticides diazinon and malathion can be used for control.

What eats a black eyed Susan?


Rabbits do not like all flowers but your black-eyed Susan, ( is on the list of perennials that are severely damaged by rabbits. Rabbits nip pencil-sized stems cleanly at a 45 degree angle. Birds on the other hand tend to shred plants and deer leave a ragged torn edge.

How do you get Black Eyed Susan seeds?

To harvest black-eyed Susan seeds, snip or pull the seed heads off the plants and place them in a brown bag as you walk through the garden. Shake the bag or open the cones to dislodge the seeds from the cones. Sift the seeds and remove any leaves or plant debris.

Why are my Black Eyed Susan leaves curling?

There isn't a specific disease that produces leaf curl in Rudbeckia. I would scout the plant for any possible insect damage. Baring that, it has to be environmental. If it were mine, I would lift the plant out of the soil, wash the leaves with insecticidal soap, and put it in a pot with a good potting soil.

How do you deadhead Black Eyed Susans?

  1. Hold the spent flower stem beneath the old flower head, where the seeds are forming.
  2. Cut through the stem 1/4 inch above the leaves or stem joint.
  3. Deadhead black-eyed Susans weekly during the bloom period, which can last from early June until October.

What are Black Eyed Susans used for?

Black Eyed Susan has diuretic properties and was used by the Native American tribes Menominee and Potawatomi to increase the flow of urine. A juice extracted from the roots has been used to treat earache. An herbal remedy in the form of an infusion from the roots is used traditionally to treat dropsy.

Where did black eyed Susan get its name?

The name, Black-eyed Susan, was probably given to the plant by early British colonists when they arrived in the new World. The genus name for all Black-Eyed Susans is Rudbeckia, named for the Rudbecks, a famous Swedish father and son both named Olof.

How do you grow Black Eyed Susan seeds indoors?

Germinating Black-Eyed Susan Seeds Indoors
  1. Prepare black-eyed Susan seeds for indoor sowing five months before the last spring frost.
  2. Prepare planting containers approximately six to eight weeks before the last spring frost.
  3. Sow two black-eyed Susan seeds in each starter pot.

What does Rudbeckia look like?

Most Rudbeckia varieties come in shades of yellow or orange, with a dark center seed head, but the flower heads are actually quite varied. There are Rudbeckia with petals in russet, bronze, and mahogany tones. For example, Rudbeckia "Cordoba" looks like a blanket flower.

What's eating my rudbeckia leaves?

Rudbeckia Petals Eaten - Knowledgebase Question. Caterpillars, beetles and snails or slugs are the likely culprits. Since there are also holes in the leaves, but you don't see any insects, I'd suspect slugs or snails are feeding at night.

What do rudbeckia leaves look like?


fulgida (left) has long, teardrop-shaped toothed leaves, dark green in color, sometimes tinged purple; the leaves of R. hirta (right) are paler in color, more narrow, less toothy, and leaves and stems are hairy.

What flowers look good with black eyed Susans?

Companion plants for this garden favorite are almost too many to list, but a few ready and reliable choices include zinnias, globe thistle, sedum, perennial hibiscus, echinacea, joe pye weed, and ornamental grasses. The yellow and golden colors look nice near shrubs with darker foliage, like smokebush and elderberry.

Are Black Eyed Susans poisonous?

Species. 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.