Mexican sunflower is so cheery, so big, and so orange that it has the power to convert unbelievers. People who walk by without noticing flowers, or even worse, notice them and shrug, will find their apathy shredded in the presence of this sun-loving, bloom-crazy, rough-and-tumble annual. In just one season, Mexican sunflower can grow as high as your head, with loads of red-orange flowers on bushy, sturdy branches for most of the summer. It thrives in hot, dry weather in poor soil. It’s also candy for bees, butterflies, and hummingbirds—and folks who thought they didn’t care about flowers.
Common name: Mexican sunflower
Botanical name: Tithonia rotundifolia
Plant type: Typically grown as annual
Zones: Annual in most zones
Height: 4 to 6 feet tall
• Sun: Full sun
• Soil: Average to poor, well-drained
• Moisture: Average to dry
• Mulch: Mulch will help preserve moisture in the soil.
• Pruning: Deadhead to prolong bloom time.
• Fertilizer: None needed.
• By seed.
Pests and diseases
• May attract slugs or snails.
• Because it’s so tall, T. rotundifolia is best at the back of a flower bed. Plant it against a wall or fence for support.
• T. rotundifolia is great for a cutting garden.
• Use as a temporary screen in summer.
• ‘Torch’ has reddish orange flowers.
• ‘Goldfinger’ stays less than 3 feet tall.
• ‘Sundance’ has bright orange flowers.
All in the family
• The genus Tithonia contains only about 10 species, all from Mexico and Central America. T. rotundifolia is the most commonly grown species in the genus.
• Asteraceae, the aster or sunflower family, is neck and neck with Orchidaceae for the title of the largest family of flowering plants in the world. Both families contain more than 20,000 species.
(Text by Elizabeth Noll, photo of Tithonia rotundifolia courtesy of Missouri Botanical Garden’s Kemper Center for Home Gardening)