Tithonia (Mexican Sunflower) in Zone 11a & 11b
Tithonia rotundifolia
Yes, tithonia (Mexican sunflower) grows in zones 11a and 11b. Start seeds indoors Nov 20–Nov 27 and plant out Jan 15–Jan 22.
When to plant tithonia (Mexican sunflower) in zone 11b
Zones 11a and 11b share the same average frost dates, so this page covers both.
Method: Either: Start indoors for an earlier harvest, or direct-sow outside for less fuss. Either works.
| Start indoors | Nov 20–Nov 27 |
|---|---|
| Direct sow / transplant outside | Jan 15–Jan 22 |
| Estimated bloom | Apr 13–Apr 20 (~88 days after planting) |
Spacing: about 2 square feet per plant (square-foot-gardening spacing). Mature height: 4-6 ft.
Plant alongside it in zone 11b
These go outside within two weeks of tithonia (Mexican sunflower) in zone 11b, so one planting day can cover them.
- NasturtiumJan 8–Jan 15
- MarigoldJan 8–Jan 15
- Angelonia (Summer Snapdragon)Jan 15–Jan 22
- Black-Eyed Susan VineJan 15–Jan 22
- Cleome (Spider Flower)Jan 15–Jan 22
- ColeusJan 15–Jan 22
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 11's season
Zone 11b is frost-free, so frost is not what limits the calendar here. What you can plant, and when, comes down to summer heat and daylength instead.
Tithonia (Mexican Sunflower) planting windows in every zone
Zone 11b is highlighted. Useful for comparing against a neighbouring zone, or for a garden somewhere else.
| Zone | Start indoors | Sow or plant out | Bloom |
|---|---|---|---|
| 2a & 2b | Apr 8–Apr 15 | Jun 3–Jun 10 | Aug 30–Sep 6 |
| 3a & 3b | Apr 18–Apr 25 | Jun 13–Jun 20 | Sep 9–Sep 16 |
| 4a & 4b | Apr 3–Apr 10 | May 29–Jun 5 | Aug 25–Sep 1 |
| 5a & 5b | Mar 29–Apr 5 | May 24–May 31 | Aug 20–Aug 27 |
| 6a & 6b | Mar 14–Mar 21 | May 9–May 16 | Aug 5–Aug 12 |
| 7a & 7b | Feb 27–Mar 6 | Apr 24–May 1 | Jul 21–Jul 28 |
| 8a & 8b | Feb 11–Feb 18 | Apr 8–Apr 15 | Jul 5–Jul 12 |
| 9a & 9b | Jan 4–Jan 11 | Mar 1–Mar 8 | May 28–Jun 4 |
| 10a & 10b | Dec 19–Dec 26 | Feb 13–Feb 20 | May 12–May 19 |
| 11a & 11b (your zone) | Nov 20–Nov 27 | Jan 15–Jan 22 | Apr 13–Apr 20 |
Bloom dates are about 88 days after the sow or plant-out date, not after starting seeds indoors.
Zone 2 sows before zone 3 here, which looks wrong and is not. USDA zones rank winter cold, not season length, and zone 2 is mostly interior Alaska, where hard winters come with warm summers. More on what a zone measures.
Good companions
No well-established companions for tithonia (Mexican sunflower).
Where to buy tithonia seeds
True Leaf Market · Burpee (each supplier's tithonia seeds)
Varieties we recommend, and where to get them:
- 'Goldfinger': The smallest of the three per Clemson, orange-gold flowers on a 2-2.5 foot plant, an even more compact option than Fiesta del Sol for the tightest spaces. Buy: True Leaf Market Full notes
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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 11b calendar · Plan your beds in the Garden Designer →
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Growing Tithonia (Mexican Sunflower) in USDA zone 11b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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