When to plant black-eyed Susans?
- Botanical name
- Rudbeckia fulgida
- Family
- Asteraceae
Black-eyed Susans are planted from March to May. They flower from July to October.
Black-eyed Susans are perennial plants.
Rudbeckia stands dry ground poorly. It is planted in spring, while the soil is still moist. The ground around it is mulched after planting and the mulch renewed every spring.
Rudbeckia is sown straight outdoors, into a prepared seed bed. A plant already growing in the garden is increased by dividing the clump.
Black-eyed Susans through the year
- planting
- sowing
- flowering
In short
Growing conditions
Are black-eyed Susans toxic to cats and dogs?
No. Black-eyed Susans are not toxic to cats and dogs.
Pests and diseases
Listed here is every problem for which the sources name this plant as a host. The problems are not listed in order of how common they are.
- Signs
- Colonies of small aphids sit on the shoot tips and the underside of the leaves. The leaf curls and puckers, and sticky honeydew is left on everything below. The viruses they carry are more dangerous than the feeding itself.
- Prevention
- Go easy on nitrogen, because soft sappy growth is what aphids are looking for. Encourage the predators (ladybirds, lacewings, parasitic wasps). Use a reflective mulch, which puts them off settling, and a strong jet of water to knock the colony off the tips.
- What to do
- Potassium soap works on contact and only while it is wet, so it has to reach the underside of the leaf. On drought-loving plants and in heat it can scorch, so apply it in the evening.
- Signs
- A white, floury coating spreads over the leaves, first on the lower and older ones. The leaf under it yellows and dries up. The fruit stays small, because the plant loses leaf surface.
- Prevention
- Plant resistant varieties, leave an airy spacing and sun, and clear the debris at the end of the season. Unlike most fungi it is not helped by wet foliage, since it spreads in heat and high air humidity, in a dry summer too.
- What to do
- Oil products meant for powdery mildew on the squash family work on contact. They do not cure a leaf that is already affected, but they stop the spread to healthy ones. On herbs cut the affected shoots back instead, since the new growth comes clean. On ornamental perennials what is left is spacing and moisture.
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Related plants
The plants below are in the same botanical family (Asteraceae).
Sources about the plant: CliniTox Pflanzengifte, GBIF Backbone Taxonomy, NC State Extension Plant Toolbox, Royal Horticultural Society, University of Illinois Extension, Wikidata. Checked between 14 and 28 August 2026. The problem descriptions also draw on: Clemson Cooperative Extension, KGZS, UF/IFAS Extension, University of Maryland Extension, University of Wisconsin-Madison Division of Extension, Utah State University Extension.