Black-Eyed Susan
Rudbeckia hirta
Cheerful, drought-tolerant perennial with golden-yellow petals and dark centers. Self-seeds freely and is loved by pollinators.
Overview
Companion Planting
Echinacea
Aster
LavenderToxicity
Rudbeckia hirta is listed as non-toxic to dogs, cats, and humans by the ASPCA; however, the foliage contains sesquiterpene lactones that may cause mild skin irritation or contact dermatitis in sensitive individuals.
Planting Tips
1 cm of water per m² equals 10 liters. Use the Watering Calculator for exact amounts.
Care Tip: Deadhead spent blooms to prolong flowering into fall; divide clumps every 3-4 years in spring to maintain vigor.
Common Pests
Aphids
Symptoms: Clusters of small soft-bodied insects on stems and leaf undersides; sticky honeydew residue and curling or yellowing leaves.
Treatment: Spray with a strong jet of water or apply insecticidal soap; for heavy infestations use neem oil.
Prevention: Encourage natural predators like ladybugs and lacewings; avoid excessive nitrogen fertilization.
Sawfly larvae (Allantus rudbeckiae)
Symptoms: Irregular holes chewed in leaves, sometimes skeletonizing foliage; small green caterpillar-like larvae visible on leaves.
Treatment: Hand-pick larvae; apply Bt (Bacillus thuringiensis) or spinosad for larger infestations.
Prevention: Inspect plants regularly in late spring/early summer; remove and destroy affected leaves promptly.
Spider mites
Symptoms: Fine stippling or bronzing on leaves; tiny webbing on leaf undersides, especially in hot dry conditions.
Treatment: Spray plants with water to dislodge mites; apply miticide or horticultural oil if populations persist.
Prevention: Maintain adequate watering during drought; increase humidity around plants and avoid water-stressed conditions.
Common Diseases
Powdery mildew
Symptoms: White to grayish powdery coating on leaves, stems, and buds; affected leaves may yellow and drop prematurely.
Treatment: Remove and discard heavily infected foliage; apply fungicide (sulfur-based or potassium bicarbonate) at first sign of infection.
Prevention: Ensure good air circulation by proper spacing; avoid overhead watering and plant in full sun.
Septoria leaf spot
Symptoms: Small dark-brown to black circular spots with lighter centers on lower leaves, progressing upward; leaves may yellow and wither.
Treatment: Remove and destroy infected leaves; apply a copper-based fungicide if disease is severe.
Prevention: Water at the base of the plant to keep foliage dry; clean up plant debris in fall to reduce overwintering spores.
Bacterial leaf spot (Pseudomonas / Xanthomonas)
Symptoms: Angular water-soaked spots on leaves that turn dark brown or black, often with yellow halos; spots may merge in wet weather.
Treatment: Remove and destroy affected foliage; copper-based bactericides can help slow spread but cannot cure infected tissue.
Prevention: Avoid overhead irrigation; space plants for good airflow and do not work among wet plants.