Tithonia (Mexican Sunflower) in Zone 6a & 6b
Tithonia rotundifolia
When to plant tithonia (mexican sunflower) in zone 6b
Zones 6a and 6b share the same average frost dates in our data, so this page covers both.
Method: Either: Start indoors for an earlier harvest, or direct-sow outside for less fuss. Tithonia (Mexican Sunflower) tolerates either.
| Start indoors | Mar 14–Mar 21 |
|---|---|
| Direct sow / transplant outside | May 9–May 16 |
| Estimated bloom | Aug 5–Aug 12 (~88 days after planting) |
Spacing: about 2 square feet per plant (square-foot-gardening spacing). Mature height: 4-6 ft.

Tithonia, better known as Mexican sunflower, is a fast-growing, heat-loving annual that produces vivid orange-red blooms on tall, sturdy stems late in the season, just as many other cut flowers are winding down.
How tithonia (mexican sunflower) fits zone 6's season
Zone 6b's frost-free window runs about 173 days, from April 25 to October 15. Tithonia (Mexican Sunflower) needs about 88 days from sowing to first harvest.
Good companions
No standout companions recorded yet for Tithonia (Mexican Sunflower).
Where to buy tithonia seeds
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See it growing
Search YouTube for "growing tithonia (mexican sunflower)" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 6b calendar · Full companion planting guide · Full plant profile · Plan your beds in the Garden Designer →

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Growing Tithonia (Mexican Sunflower) in USDA zone 6b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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