The Mexican sunflower, Tithonia rotundifolia, likes full sun and can grow as tall as 6 to 8 feet.
The most common variety is ‘Torch', which has, as the name suggests, a bright orange flower. These impressive annuals have hairy stems with velvety green leaves and 3-inch wide, daisy-like blooms.
Water them well during dry weather as they crave moisture, and stake them if they are growing in an exposed site. Pinch off spent blooms to extend flowering. The golden variety is ‘Goldfinger', and a more compact and less brassy yellow is ‘Golden Torch'. They all grow easily from seed.
The blooms last about 3 to 4 days in a vase but only if the stems are sealed. Either sear the end of each stem over a flame or dip them in boiling water. These plants are often grown to attract bees and butterflies to a garden and are easy to start, as the seeds can be sown directly into the garden soil about 2 weeks after the last frost date.
Grow the plants about 18" apart as they bush out. They do well as a background in a border or along a fence. They are also sometimes used as a flowering screen or hedge for privacy in small yards, so are versatile as well as easy.