277 Tithonia rotundifloraCommon Names: Mexican sunflower, tithonia Family: Asteraceae (aster/daisy Family)
Mexican sunflower is a warm season annual with a stout, gangly habit, growing to 5-6 ft (1.5-1.8 m) tall and 3-4 ft (0.9-1.2 m) wide. The leaves are coarse, 3-lobed, 4-10 in (12.7-25 cm) long and 2-4 in (5-10 cm) wide. The leaves and stems are covered with a soft downy fuzz. The numerous flower heads are brilliant red-orange, like daisies or zinnias, and about 3 in (7.6 cm) across. The beautiful cultivar, 'Torch', was named an All America Selection and is the probably the most popular. Dwarf cultivars are also available including 'Goldfinger' and 'Fiesta Del Sol' that grow to about 3 ft (0.9 m) in height and perfect for smaller gardens.
There are about 10 species of Tithonia native to Mexico and Central America.
CultureLight: Likes full sun, but can tolerate filtered sun or partial shade. Moisture: Needs well-drained soil. Mexican sunflower is heat and drought resistant but water when dry for a good look. Hardiness: USDA Zones 5 - 10. Killed by frost, but will reseed itself next spring. Propagation: Seeds.
Mexican sunflower is beautiful in cut flower arrangements, but the flower heads are borne on fragile hollow peduncles (flower stems) that must be cut carefully with a sharp knife lest they bend and collapse. Plant Mexican sunflower behind beds or borders where their coarse texture, rangy habit and vivid flowers will stand above less boisterous plantings. Unless you're growing one of the compact varieties, they will need plenty of room.
Few plants as large and spectacular as Mexican sunflower can complete two generations in a single summer. In the southern U.S., Mexican sunflower seeds planted in March or April will produce plants that flower and go to seed in June. Those seeds will fall to the ground, germinate, and produce a second generation of flowers that will mature before the first frost in October!
Mexican sunflower is one of the best flowers you can grow for attracting butterflies. In late summer, a stand of tithonia may attract a half dozen or more butterfly and skipper species with one or more individuals on every single blossom!
The composite family is so named because their members have flower heads that consist of many flowers, usually of two different types. Ray flowers look superficially like petals around the margin, and disk flowers are crowded together in the center of the composite flower head. Both kinds of flowers may have pollen-producing stamens and seed-producing ovaries. Use a hand lens to see these parts for yourself.
Steve Christman 08/11/97; updated 06/07/97, 12/06/99, 05/19/03, 09/17/03, 09/03/06, 03/23/16