Mexican sunflower, Tithonia rotundifolia

Mexican sunflower, Tithonia rotundifolia, is a tall plant.

The genus Tithonia in the daisy family (Asteraceae) includes 10-15 species of bushy annuals, perennials and shrubs native to Mexico and Central America that have large, brightly colored daisy-like flowers on thick stems. Mexican sunflower, T. rotundifolia, is a vigorous, drought tolerant warm season annual that is easy to grow in the ornamental garden with other common names of red sunflower of just tithonia.

Tithonia plants grow 4-6+ feet tall, with a large central stalk and a somewhat gangly branching habit. The stems can be brittle. The dark green leaves are ovate to deltoid (triangular) in shape, with serrate to crenate margins. The coarse leaves are usually entire but occasionally will be three lobed. The foliage and stems are covered with a soft downy fuzz, and the underside of the leaves are hairy.

The foliage of Mexican sunflower is coarse and hairy (L); the ovoid to deltoid leaves have serrate margins and are usually entire (C) but may be three lobed (R).

Flowers are produced from mid-summer until frost. The solitary flowers are borne on fragile hollow peduncles (flower stems) that are susceptible to being bent and are often broken by birds. Each 3-inch blossom has a number of bright red to orange ray flowers surrounding the central yellow disk flowers.

Thick, fuzzy buds (L) open (LC) to reveal bright red to orange ray flowers (C) surrounding yellow disk flowers (RC) that remain for a while after the ray flowers fall off (R).

Tithonia seeds.

The flowers are attractive to a wide variety of bees, butterflies and hummingbirds, and can be used as cut flowers. Deadheading spent flowers will prolong blooming. The flowers are followed by grey to black flattened triangular seeds that are easy to collect to save to grow in subsequent years.

Many pollinators visit tithonia flowers including (L-R) bumblebee, longhorned bee, another wild bee, syrphid fly, monarch butterfly and tiger swallowtail.

Use tithonia at the back of borders and beds as a backdrop for shorter plants.

Because of its tall stature, rangy habit and coarse texture, this annual is best at the back of borders and beds to form a backdrop for shorter plants. It can be used as a seasonal screen (especially if grown from transplants started early in the season). Use in mixed or annual borders with tall zinnias, coreopsis, and other flowers in hot colors for a high-energy planting, or tone down the brilliant orange-red flowers by combining with purple flowers and larger plants with dark-colored foliage, such as annual ornamental millet or castor bean or in mixed beds with woody plants such as smokebush or ‘Diabolo’ eastern ninebark.

Tithonia does best in full sun in well-drained soil.

Tithonia grows best in full sun in poor to average, well-drained soil. Avoid planting in rich soil or heavy fertilization that with promote excess foliage and weak stems. Pinch back plants to encourage bushier growth and sturdier plants less likely to fall over, but plants often need to be staked to remain upright. Shelter from strong winds if possible. It has few pest problems and is not favored by deer.

Grow tithonia from seed, either planted directly in the garden at the last frost date or started indoors 6-8 weeks before the average last date of frost for earlier blooms. Sow shallowly as as light is required for germination. Plant in the garden about two feet apart to provide support for adjacent plants, or place staked plants 3-4 feet apart. Since the plants tall with brittle stems, try to provide shelter from strong winds, but even in areas that are not windy these plants benefit from staking. It needs warm sunny weather to grow well so may not do much early in the season. In cool summers, late-planted direct-seeded plants may not bloom.

Tithonia ‘Fiesta del Sol’.

Only a few cultivars are generally available:

  • ‘Fiesta del Sol’ – is a shorter cultivar that only grows about 3 feet tall. It was an AAS award winner in 2000.
  • ‘Goldfinger’ – is a short variety (2-2.5 feet tall) better suited to small gardens with orange-gold flowers.
  • ‘Torch’ – is the most commonly offered cultivar, winning an AAS award in 1951.
  • ‘Yellow Torch’ – has apricot yellow-orange flowers.

– Susan Mahr, University of Wisconsin – Madison

newline]

Download Article as PDF


Additional Information

8 comments

  1. I’d love to locate some of the shorter cultivars. I love the bright color of the Mexican sunflower but my garden would not handle this very tall plant.

  2. Not only do the monarchs love’em so do the hummingbirds! I plant from seed outside after last frost. The short variety blooms a bit earlier while the taller variety takes a bit longer; nice way to have a longer season. I plant next to a larger shrub in full sun to give the Tithonia a bit of protection and support.

  3. Very pretty, but very large plant. Interesting to read about but with my tiny city lot would be overwhelming.

  4. These can be sen at the Dousman Stagecoach Inn. Lovely! I was told they were purchased from Shady Lane Nursery.

  5. This looks like an interesting flower for my garden at the edge where the soils are dryer

  6. This looks like an interesting flower for my upper garden that gets a lot of sun and in our sandy soil, dries out quickly. I would probably plant them against my fence for support as they grow so tall, and is protected a bit from the wind by a maple tree to the north, and our house to the east. Also, is deer resistant, always looking for something the deer don’t like!

  7. I have never seen these at any nurseries or garden centers around here. I’m assuming if I wanted to grow them I would have to order a seed packet. But then sounds like I can harvest the seeds after that. I wonder if they will self-seed and grow on their own in the garden like nigella does.

    • Milaegar’s in Racine had them in 4″ pots this Spring.

Leave a Reply

Your email address will not be published. Required fields are marked *

While the University of Wisconsin Colleges and the University of Wisconsin - Extension do not regularly review content posted to social media sites, the administration shall have the right to remove any content from any official site for any reason, including but not limited to content deemed threatening, obscene, a violation of intellectual property rights or privacy laws, or otherwise injurious or illegal.

Public opinions/comments posted on this site do not necessarily reflect those of UW-Extension/UW Colleges.