Looking for a flower that doesn’t mind the heat? Tithonia (also known as Mexican sunflower) is a drought-tolerant and heat-loving annual plant native to Mexico and Central America. Bees, butterflies, and hummingbirds love the bright blooms. Tall branching plants bloom for several months (right up until frost), and make an excellent cut flower. Learn how to grow Mexican sunflowers and add them to your garden.
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5 Tips for How to Grow Mexican Sunflowers (Tithonia)
1. Plant tithonia at the right time
Tithonia is a frost-tender annual flower that grows best from seed. Tithonia seeds need light to germinate; cover lightly (¼”) with soil. Mark the planting area well and be patient because seeds take between 1-3 weeks to sprout. Space seeds about 2 feet apart.
In warm climates, plant tithonia seeds directly in the garden when soil warms to about 60°F. For earlier blooms, start seeds indoors 6-8 weeks before the last frost date.
In the low desert of Arizona, plant tithonia seeds directly in the garden from February through early May. Tithonia begins blooming around July and the blooms often last through early December.
In cooler climates, start seeds indoors 6-8 weeks before the last frost date and plant outside when soil warms to about 60°F.
2. Choose a location with plenty of sun to plant Mexican sunflowers
Tithonia prefers warm weather and grows best in full sun (even full Arizona sun). Mexican sunflowers grow well in most types of soils. The soil should be well-draining.
3. Give tithonia plants room to grow
Mexican sunflower plants grow large, often ranging from 4 to 6 feet in height and up to 4 feet wide. Growing tithonia plants in the back of a border provides a colorful backdrop for smaller plants.
Plants spaced about 2 feet apart will provide support for each other. Grow staked plants 3 to 4 feet apart. Leaving enough space between plants helps provide adequate airflow and makes plants healthier.
For square foot gardening, allow 2 square feet per plant.
4. Care for Mexican sunflowers correctly as they grow
Overall, tithonia is an easy plant to grow and it’s fairly pest and disease resistant.
- Tithonia does not require additional fertilization.
- Plants are drought-tolerant, but need regular water in hot summer areas with little rainfall.
- Provide support by staking for tithonia as it grows; this is especially important in windy areas.
5. Enjoy the blooms
Tithonia blooms are between 2”-3” wide. The colors range from yellow to orange and almost red depending on the variety you grow. The blooms, nectar, and seeds attract a large variety of wildlife including butterflies, bees, and hummingbirds.
Mexican sunflowers make excellent cut flowers. Handle tithonia stems gently as the flower stalks are hollow and somewhat brittle.
Keeping spent blooms deadheaded will encourage more blooms. At the end of the season, allow several blooms to remain on the plant and collect the seeds inside to plant the following year.
PK
Tuesday 15th of November 2022
Transplanted Oct. of 2021. It came up spring of 2022. Grew about 4 ft. wide and a little over 5 ft. tall. Full sun most of the day till about 4 or 5 in the afternoon. Never a single bloom. We had our first hard freeze this week. Sadly no flowers, any idea as to why.
Angela Judd
Monday 21st of November 2022
That is strange, I'm not sure.
Taryn Hill
Monday 25th of July 2022
Does anyone know what type of soil they like? I am growing Tithonia Diversofloria. I would like to mulch with pine needles but they are acidic. Thank you in advance for any help!
Angela Judd
Friday 29th of July 2022
They tolerate poor soil. Mulching with pine needles is fine.
Lazer
Saturday 18th of September 2021
Been growing Mexican sunflowers for years in my butterfly garden. They draw all sorts of butterflies and I love the nectar from this beautiful plant. I collect seeds and plant them every three or four months
Angela Judd
Sunday 19th of September 2021
Sounds lovely!
Susan Grasso
Friday 27th of August 2021
Hello, I live in eastern Pennsylvania and have planted the mexican sunflower for the first time this year. All of the plants are blooming, except one.. The one that is not blooming has a stem about 4 -6" around and is about 8-10' tall. I've given it miracle grow and have pruned some of the branches back. It has tons of buds, but no blooms. How can I get it to bloom. Thanks in advance for your advice
Ron Hovanec
Friday 22nd of October 2021
Stop giving it Miracle Grow. The nitrogen is encouraging plant growth and not flowers.
Angela Judd
Saturday 28th of August 2021
hmmmm..... does it get enough sun? It sounds like it's a good size. I would hold off on any more pruning to see if it will bloom.
Tricia
Monday 31st of May 2021
Good advice! I am wondering: Can tithonia be pruned into a smaller bush? I have some coming up from last year's Big Mistake. I seeded what I thought were small zinnia seeds, but at 8' + I realized those were definitely not zinnias! Now seedlings have come up and I know I need to either move them or trim back? Which should I do? I'm in Atlanta area and heat is already giving transplants problems.
Ron Hovanec
Friday 22nd of October 2021
There are varieties that only grow 3' to 4" tall.
Angela Judd
Tuesday 1st of June 2021
They do tend to get large. You can keep it somewhat trimmed but it will get large. I wouldn't attempt transplanting it at this point, just do the best you can.