The Mexican Sunflower, Bolivian sunflower, tree marigold or the Tithonia plant are considered an annual flowers, native to both Central America and in Mexico, where varieties of the ponytail plant and spineless yucca trees also call home.
Locals refer to it as the “Golden Flower of the Incas” due to its large, showy bursts of daisy-like flowers.
The name “Tithonia” pronounced [Tith-oh-nee-uh] for the genus came from Greek mythology by a French botanist in 1799. Tithonus was a loved by the dawn-goddess Aurora.
Tithonia Plant Facts
- Origin: Mexico and Central America
- Family: Asteraceae
- Botanical Name: Tithonia [Tith-oh-nee-uh]
- Common Name: Mexican sunflower, Japanese sunflower or Nitobe chrysanthemum
- Plant Type: annual flower
- Size: 3′ – 6′ feet
- Flowers: bright orange, red or yellow
- Bloom: summer until first frost
- Hardiness: USDA hardiness zone 3 -11
- Exposure: Full sun or part shade
- Soil: good well-drained soil
- Water: Average water needs
- Fertilizer: all-purpose fertilizer
- Propagation: seed
- Pests & Problems: no serious pest problems, deer resistant
The plant grows to a range of anywhere from 36″ inches up to more than 60″ inches in height.
A dwarf selection ‘Fiesta del Sol’ grows about 30″ inches tall and is great for small gardens.
It’s characterized by flashy bright orange, yellow and red flowers showing off their bright hues.
Moreover, the flowers look great as it appears in contrast with its dark green leaves.
Butterflies love to fly around and pollinate Mexican sunflowers. This makes it a good addition to a flower garden if you want it to be visited frequently by butterflies and hummingbirds.
The bright flowers of the Mexican sunflower is a butterfly magnet and a favorite of the Monarch butterfly.
Other varieties of butterflies that sees its nectar as a treat include eastern tiger swallowtail and pipevine swallowtail.
The Mexican Sunflower (Tithonia diversifolia) proves to be a stunner, especially for those who favor sunflowers.
Much like its namesake, the Tithonia diversifolia makes an invaluable, colorful addition to your garden beds and is easy to grow. Here are some ways to grow your Tithonia torch plant beautifully.
NOTE: Another species Tithonia rotundifolia (red sunflower) is similar in size and growth habitats. The flowers are similar in shape, slightly smaller and red or bright orange flowers.
How To Grow The Mexican Sunflower Tree Plant
The Mexican Sunflowers love full sun, and doesn’t like the cold weather. Plant Tithonia rotundiflora where they receive generous sun all throughout the day. The USDA hardiness zone for growing are 3 – 10.
Adequate soil should suffice in caring for the Tithonia plants; keep a well-drained soil to remove excess moisture. Before planting, put in a good amount of compost for your Mexican Sunflower to grow healthy and strong.
Mexican sunflower plants are drought tolerant making it a great summer plant. Mix in a general-purpose fertilizer as plants grow to promote a healthy surge.
The plant starts blooming 2″ to 3″ inches of beautiful flowers from late summer to fall season.
Carefully remove spent Mexican sunflower blooms deadheading to make room for the new ones, will encourage the plants to grow flowers for a longer time, even producing bright blooms even in late fall.
For the best results, place the Tithonia plants at the back border, and in groups. They can reach anywhere from 36″ to 60″ inches tall upon maturity. Stake plants for straight growth and to prevent them from falling over. When planting in containers, prepare large pots for optimal growth conditions.
Tithonia makes good cut flowers, but handle cut flowers gently as the flower stalks are hollow and brittle.
You can see the Mexican Sunflowers get lots of activity in the video below!
Tithonia “Torch” A Brief History
When new to the world of garden flowers we find new discoveries all the time. Tithonia may be new to many but the “Mexican sunflower plant” has a history since the naming of the Tithonia genus in 1799.
For example, the plant known as Tithonia “Torch” which is still available today was “new” to the plant world in 1951.
- The plant graced the cover of the January 1951 edition of Popular Gardening Magazine.
- Torch was an All-America Silver Medal Winner
- Described as: “Striking, orange-red and easy to grow, Torch is not too tall for the garden and literally enjoys the hot weather.”
- From Harris Seeds 1951 Catalog: “Torch Tithonia produces a multitude of long-stemmed orange-scarlet blooms often 3″ inches across. The plants grow waist high and start blooming early. As easy to grow as Zinnias; not troubled by insects or diseases. You’ll want this new flower in your garden.”
The editors shared in 1951:
“Tithonias of the past made tall, weedy plants and they flowered late, but ‘Torch’ rarely exceeds 4′ feet and will begin to flower in early summer from spring-sown seed.
Torch Tithonia started to bloom by July 12th and grew up to make a 4′ foot bushy plant with heavy leaves and brilliant orange flowers measuring 4″ inches across and kept coming until cold weather.”
Tithonia Plant Propagation
Grow Tithonia Mexican sunflowers from seed. At the onset of cold weather, start them indoors. During warmer months, set them outdoors. Remember keeping the soil moist until the Mexican sunflower seeds sprout is key.
Growing Tithonia From Seed Outside
Start the sowing process once the last frost passes. Soil should reach a temperature of 60° degrees Fahrenheit.
Mark the site well as the seeds might take a longer time to appear (about 10 to 21 days). Cover with shallow soil, about a fourth inch, and space the seeds about 6″ inches apart. The spacing should be around two feet to three feet apart.
Sowing Seed Inside
If cold is not a problem in your area, start Tithonia seeds outside. Otherwise, start them inside about 8 weeks before the last frost.
The seeds should be placed shallowly on the soil surface to allow germination. The germination process takes anywhere from 7 to 14 days with an optimal temperature of 70° degrees Fahrenheit.
You may start sowing from March till April in pots, trays, etc with a propagator or in a warm place for best results.
The young Mexican sunflower seeds should be transferred outdoors after the last frost of spring, at a 20″ inch spacing. Find the sunniest spot in your garden and plant your Mexican Sunflower in light soil.