Centratherum punctatum aka Larkdaisy

Centratherum punctatum is in the daisy family, Asteraceae. It has several common names. These include Brazilian buttonflower, bachelor’s button, and larkdaisy. Kew places its native range in tropical South America. There, it grows in a tropical climate with dry seasons. Its stems are soft. It can live as a tender perennial for a few years. Gardeners also grow it as an annual where winters freeze.

Plants grow fast and form dense clumps that spread. Garden heights reach about 1–2 feet [0.3–0.6 metres]. Their spread reaches about 2–4 feet [0.6–1.2 metres]. RHS gives smaller upper limits for both height and spread. These are 1.6 feet [0.5 metres] tall and 3.3 feet [1 metre] wide. Thin, reddish stems bear simple leaves, each with one blade. The leaves grow in turn along the stem. The oval leaves have coarse teeth and pinnate veins. These veins branch from one main vein. Leaf shades range from olive to light green. The leaves have a light scent and a fine texture. They fall without a marked change in autumn colour.

Round flower heads rise above the leaves through summer and autumn. The soft, fluffy blooms range from lavender-blue to pink. Each head measures about 0.08 feet [0.025 metres] across. In tropical climates, blooms may last through the whole year. The flowers draw insects that pollinate them, including butterflies. Small, brown fruits follow the flowers but add little display. They are oval, with a dry, hard covering.

Give this plant full sun and soil that drains well. The Florida guide also allows a site with some shade. RHS advises a spot with shelter for growth. It accepts sand, loam, and clay if they drain well. It can grow in acid, neutral, or alkaline soil. It copes with drought, but freezing weather kills it. The Florida guide lists USDA zones 9–11 for perennial growth. RHS rates its cold tolerance as H2. In colder gardens, grow it as a summer annual.

Its low, sprawling form suits ground cover and border edges. It can trail over walls or spill from containers. Use it in rock gardens, on slopes, or in informal plantings. Sow seed in spring, or raise plants from cuttings. Plants may shed seed and sprout new plants next spring. RHS says the plant needs no pruning. Both garden sources report few serious pest or disease problems. The supplied evidence gives no food uses. It also gives no assessment of toxicity.