Cosmos caudatus aka Cosmos

Cosmos caudatus is a herb in the daisy family, Asteraceae. Its native range runs from Mexico into southern tropical America. Kew places it in the tropics, where dry seasons occur. Useful Tropical Plants gives a wider range across the tropics. This does not mean it is native throughout that range. Plants have escaped gardens and now grow elsewhere. The RHS says it is not native to Britain or Ireland.

Kew lists this species as an annual: it lives one year. Useful Tropical Plants says it can also live for several years. That source gives heights of about 1–6.6 feet [0.3–2 metres]. It also lists a height of 3.3 feet [1 metre]. These figures suggest a range, not one fixed full-grown height. They give no clear height range for plants in gardens. The species accounts do not say how wide it grows. They give no close details of its stems or leaves.

Young leaves and shoot tips are its main known use. People pick leaves from wild plants for local food. They eat the tender growth raw or cook it. The source lists salads and stews as uses for these parts. Useful Tropical Plants rates its food value three out of five. It also says people could grow it as a vegetable. This is a possible use, not proof of an established crop. The evidence gives no taste details or times to pick it.

The accounts list seed as the means to grow new plants. They do not say how to sow seeds or sprout them. Nor do they state light, soil, or water needs. Its home climate alone cannot tell us those garden needs. The evidence gives no hardiness zones or frost limits. The species accounts give no bloom season or fruit details. The RHS describes flowers for the genus, not this species. Those wider traits cannot tell us this plant’s own flower traits.

In some places, garden escapes now grow and spread without help. They grow by roads and on disturbed, unused ground. This gives grounds for care, as it could become weedy. It does not prove that it invades every region. Useful Tropical Plants lists no known hazards. It lists no known medical uses or other uses, either. The lack of known hazards does not prove safety for pets. The evidence names no pests or diseases.