The Mexican Sunflower is a bold, cheerful plant that brings brilliant colour and a tropical feel to the garden. Native to Mexico and Central America, it has been grown for centuries both for its beauty and its usefulness. There are a few species commonly grown under this name – the most popular being Tithonia rotundifolia, with bright orange-red flowers, and Tithonia diversifolia, sometimes called the “tree marigold,” which grows taller and bushier.

These sunflowers are not true Helianthus sunflowers but belong to the daisy family (Asteraceae). They’re loved worldwide for their long-lasting blooms, which light up the garden from midsummer to autumn and attract a constant parade of bees, butterflies, and even hummingbirds in their native lands.

While not generally eaten as a human food, Mexican sunflowers are valued in sustainable gardening and farming. Their leaves are high in nitrogen, phosphorus, and potassium, making them excellent “green manure” when chopped and dropped into garden beds. In some parts of Africa and Asia, farmers use them to enrich soil naturally. In folk medicine, Tithonia diversifolia has also been used in teas and poultices, though it’s best appreciated today for its ornamental and ecological value.

Mexican sunflowers are fast-growing annuals (or short-lived perennials in frost-free zones). Depending on the species, they can grow anywhere from 1.2 to 3 metres tall, with bushy growth and large, velvety leaves. They thrive in full sun and poor soils, often flowering more abundantly when conditions aren’t too rich. Their blooms are daisy-like, in shades of fiery orange, red, or yellow, and appear for many weeks, keeping the garden alive with colour.

How to Grow From Seed:
Sow Mexican sunflower seeds directly into the garden in spring once the danger of frost has passed, or start them indoors 4–6 weeks earlier if you want a head start. Plant seeds about 0.5–1 cm deep in well-draining soil and keep moist until they germinate, usually in 7–14 days.

Space seedlings 40–60 cm apart for smaller types (Tithonia rotundifolia) or up to 1 metre apart for the larger Tithonia diversifolia. Give them full sun and don’t over-fertilise, as too much nitrogen encourages leafy growth at the expense of flowers. Once established, they’re drought-tolerant and low-maintenance, producing masses of blooms right through summer and autumn.

Deadheading spent flowers will encourage even more blooms, but leaving some at the end of the season allows you to collect seeds for next year.