What is the black stuff on my Black Eyed Susans?

Asked By: Khaoula Nigorra | Last Updated: 25th February, 2020
Category: food and drink vegetarian diets
4.7/5 (254 Views . 32 Votes)
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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Correspondingly, how do you get rid of black spots on black eyed Susans?

Chlorothalonil (Daconil) is a common fungicide that's effective for this leaf spot disease. Organic gardeners can use copper-based fungicides. You can do a few other things to discourage a repeat of the disease. One is to rake and remove fallen leaves since that's a good source of spores to keep the disease active.

Beside above, what's eating my black eyed Susan? As with many other types of garden plants and flowering perennials, aphids are the primary insect pest of black-eyed Susans. They indirectly contribute to mold infections by feeding on plant sap and then excreting a substance called honeydew, which encourages growth of black sooty mold.

Similarly, it is asked, 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.

Do Black Eyed Susans multiply?

Black-eyed Susans produce fibrous roots that spread horizontally in the soil. If you pull black-eyed Susans from your garden and leave some root pieces behind, the clumps eventually produce a new plant. You can create a constant supply of new flowering plants by dividing the clumps in the fall after blooming.

32 Related Question Answers Found

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.

Should I deadhead Black Eyed Susans?

Deadheading Black Eyed Susan flowers is not necessary but can prolong the blooming period and prevent the plants from seeding all over your landscape. After the blooms fade, the flowers turn to seed, which goldfinches, chickadees, nuthatches and other birds feed on throughout the fall and winter.

How long do Black Eyed Susans last?

The flowers of the black-eyed susan, which occur singly atop the tall stems, make attractive additions to cut flower arrangements, with a “vase life” of six to 10 days.

What kills Black Eyed Susans?

To be completely safe, spray the ground with an herbicide that is made to kill weeds. You can find this herbicide at a garden center. You have to be careful, however, that you make sure you do not get the herbicide on any neighboring plants, as it can kill them.

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 fertilize Black Eyed Susans?

Fertilizer. For best black eyed susan care, you don't want to overfertilize your soil. Overfertilization causes the flower stems to droop or become weak. If you're going to fertilize at all, use a general-purpose slow-release granular fertilizer sparingly once or twice a year.

When Should Black Eyed Susan seeds be planted?

Plant black-eyed Susans when the soil temperature has reached 70°F for best seed germination. In many parts of North America, the planting period is March to May. The flower will flower June to September. Germination takes 7 to 30 days.

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.

What does a Black Eyed Susan Leaf 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.

Why do flowers get moldy?


Mold can be caused by a number of things including poor maintenance, over-watering, or lack of sunlight. Mold growing on the houseplants' soil or on the actual leaves of the plant is both harmful for the members of the household and for the plants. Luckily, there are ways of getting rid of this mold.

How do you get rid of rust fungus?

How to Control Rust Fungi
  1. Remove all infected parts and destroy them. For bramble fruits, remove and destroy all the infected plants and replant the area with resistant varieties.
  2. Clean away all debris in between plants to prevent rust from spreading.
  3. Avoid splashing water onto the leaves, as this can help spread rust.

What kills rust on plants?

Regular, over-the-counter aspirin can help control several fungal diseases affecting your plants, including powdery mildew, black spot and rust. According to "Fine Gardening" magazine, dissolving two uncoated aspirin tablets that are 325 milligrams each in 1 quart of water is a natural foliar spray that will kill rust.

Why is my black eyed Susan vine not blooming?

As soon as cooler weather starts back up again in September it should start to bloom again in force. Other than that, make sure your plant is in full sun, you are watering it sufficiently and you are not over-fertilizing it. Too much nitrogen can cause plants to produce more foliage and less blooms.

How do you divide black eyed Susan plants?

To divide your black-eyed Susan flowers, first cut back the plants so they will be easier to move. Then dig a trench around the clump you want to divide, beginning at the plant's drip line. Carefully cut down into the ground at an angle to sever the roots until you can lift the plant out of the ground.

Do Black Eyed Susans attract flies?


Black-eyed Susans Attract Pollinators and Other Beneficial Insects. These are shallow enough that even small wasps and flies can drink from them, and many small wasps and flies are predators or parasitoids of pest insects. These tiny, dark flowers bloom from the outer rim of the eye and progress inwards with time.

What is eating my anemone plants?

Sap-Sucking Insects
Silverleaf and greenhouse whiteflies and several aphid species attack anemone flowers. They and tiny, pear-shaped aphids colonize the undersides of foliage, consuming leaf fluids and secreting a sticky waste called honeydew. Heavy infestations of either insect deprive anemones of nutrients.

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.