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How to Grow Mexican Sunflowers

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.  

How to Grow Mexican Sunflower

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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. 

How to Grow Mexican Sunflowers: 5 Tips for Growing Tithonia

Perpetual Flower Planting Calendar for Zone 9B

Flowers to Plant Outside & Seeds to Start Indoors Each Month in the Low Desert of Arizona.
PLANTING GUIDE: Each month lists annual flowers and bulbs to plant outside & seeds to start indoors.
BLOOMING GUIDE: Photos show what may be in bloom that month.

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.

How to Grow Mexican Sunflowers: 5 Tips for Growing Tithonia

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. 

How to Grow Mexican Sunflowers: 5 Tips for Growing Tithonia

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.
How to Grow Mexican Sunflowers: 5 Tips for Growing Tithonia

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.

How to Grow Mexican Sunflowers: 5 Tips for Growing Tithonia
How to Grow Mexican Sunflowers: 5 Tips for Growing Tithonia

At the end of the season, tithonia plants are an excellent choice for chop and drop mulch. Learn more here:

Plant Heat-Tolerant Cover Crops Instead Take the summer off!

In this article, learn more about using cover crops during summer to improve garden soil.

Visual planting guides for vegetables, herbs, fruits, flowers & vines.

If this post about how to grow Mexican sunflowers was helpful, please share it:

Steven Furst

Sunday 23rd of July 2023

I have a couple of Tithonia plants in full sun grown from seed from purchases seed pack that won’t flower at all. ( it’s now mid July in texas !). Have grown them in same spot before with great success. And I’m bummed with this big ugly giant with no flowers? Anything I can did to stimulate flower growth?

Angela Judd

Wednesday 26th of July 2023

Might be too much nitrogen if there is an abundance of leaves. Try a fertilizer for blooms low in nitrogen if it's not too hot.

Katie F

Wednesday 24th of May 2023

Could I plant in a large container? Do you think it would do well? I was given one, but don’t have the ground area to plant it until I make some changes and was thinking of using a large half ‘wine barrel’ planter full sun.

Angela Judd

Wednesday 24th of May 2023

That sounds like a great idea!


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.


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!