Gomphrena globosa — globe amaranth — makes small, clover-like flower heads out of stiff, papery bracts rather than true petals, which is why the color holds for years after drying with no special handling: just cut and hang. Native to Central America, it shrugs off the heat and drought that wilt most annuals, blooming from early summer through the first hard frost in magenta, purple, pink, white, and orange.
Seed germinates slowly and unevenly, often taking two to three weeks; soaking seed overnight before sowing speeds it along. Start indoors 6–8 weeks before last frost for an earlier bloom, or direct sow once soil is reliably warm. Established plants tolerate poor soil and neglect, and the flowers draw butterflies and bees through the hottest stretch of summer. In parts of Asia the dried flowers are steeped as a traditional remedy for cough and asthma.
Root rot
Plants wilt, yellow, and stunt even in moist soil; lower stems and roots turn brown, soft, and mushy and the plant may collapse. Most common in heavy, wet, or poorly drained ground.
Improve drainage and stop overwatering, and never plant too deep. Lift and destroy badly affected plants along with the soil around the roots. Grow in raised or free-draining beds to prevent it returning.
Fungal leaf spot
Brown or purplish spots on the leaves, often ringed with a yellow halo, that spread and merge in warm, humid, or wet weather; heavily spotted leaves yellow and drop early.
Pick off spotted leaves and clear fallen debris to remove overwintering spores. Improve air circulation by thinning, and water at the base so foliage dries quickly. If it persists, apply a copper- or sulfur-based fungicide at the first sign.