Black-eyed Susan is the quintessential North American wildflower — golden-orange ray petals around a dark brown central cone, blooming from midsummer into autumn. It is a biennial or short-lived perennial that self-seeds freely and naturalises into colonies. The flowers are among the most cheerful and useful in the late summer cutting garden, combining easily with almost anything in the season.
Cut when the ray petals are fully open and the disc is still firm. The vase life is good — 7–10 days with clean water. The dried seed heads are attractive left standing through winter and provide food for finches. Exceptionally easy: drought, poor soil, and heat are no obstacle once established.
Powdery mildew
White or grey powdery coating on leaves — usually starting on older growth in humid conditions or when nights cool.
Improve air circulation by thinning plants. Apply neem oil or potassium bicarbonate spray at first sign. Avoid overhead watering.