Tithonia rotundifolia (Mexican Sunflower)

Thriving in the summer heat, Tithonia rotundifolia, also known as Mexican Sunflower, is a vibrant and fast-growing annual plant prized for its abundant and joyful blossoms, making it a popular choice in gardens.

Mexican Sunflower: An In-depth Look

The Mexican Sunflower is a tall, bushy annual boasting large, bright orange-yellow, daisy-like flowers and coarse, heart-shaped leaves, creating a striking presence in gardens with its vivid and showy blooms.

Native: It originates from Mexico and Central America. It has been widely introduced as an ornamental and is now naturalized across Africa, Asia, South America, the West Indies, the southern United States, and Australia.

Plant Type and Habit: As an annual, it completes its life cycle in one growing season. It has a bushy, upright growth habit with robust stems.

Size: It reaches a height of 4-6 feet (120-180 cm) and a spread of 2-3 feet (60-90 cm). Staking may be required.

Flowers: The flowers are large, showy, and daisy-like, with bright orange or yellow petals surrounding a central disc. They can be up to 3 inches (7 cm) in diameter.

Bloom Time: Blooming typically occurs mid-summer until the first frost.

Foliage: This bushy plant features large, deep green leaves, heart-shaped to lobed, and covered with soft hair

Uses: Mexican Sunflower is mainly used for ornamental purposes in gardens. It is an ideal addition to beds and borders, cottage gardens, gravel gardens, and cutting gardens, as it makes excellent fresh-cut flowers.

Hardiness: Being a warm-weather plant, it is grown as an annual in USDA hardiness zones 2-11.

Toxicity: There are no significant concerns regarding toxicity to humans or pets.

Wildlife: Mexican Sunflower attracts pollinators such as bees, butterflies, hummingbirds, and other pollinators and beneficial insects.

Deer and Rabbit: Mexican Sunflower is resistant to deer.

Drought: It has good drought tolerance, making it suitable for xeriscaping or gardens with low water availability.

Invasiveness: Mexican Sunflower spreads rapidly and can outcompete native vegetation. It is listed as invasive in Zimbabwe, Zambia, Kenya, Uganda, and Tanzania.

Mexican Sunflower Growing Tips

Light: Prefers full sun for optimal growth and flowering. At least 6 hours of direct sunlight daily is ideal.

Soil: Thrives in well-drained soil. Tolerates a range of soil types, including dry and poor soils, but rich, fertile soils should be avoided as the plant may develop excess foliage.

Watering: Regular watering is needed, especially during dry spells. However, it’s drought-tolerant once established. Avoid overwatering.

Fertilizing: Benefits from a balanced, slow-release fertilizer applied at planting time. Excessive feeding can lead to more foliage and fewer flowers.

Pruning: Deadheading spent flowers encourages more blooms. Prune to shape the plant and promote bushier growth.

Propagation: Easily propagated by seeds. Sow indoors 6-8 weeks prior to the last spring frost date or sow directly in the garden after the danger of frost has passed.

Pests and Diseases: Generally pest-resistant. Watch for aphids and whiteflies. Good air circulation and well-drained soil help prevent fungal diseases like powdery mildew.