Mexican Sunflower Growing Guide

Tithonia rotundifolia

Crop Rotation Group

Miscellaneous ●

Soil

Fertile, well-drained soil enriched with plenty of compost.

Position

Full sun.

Frost tolerant

No. Mexican sunflowers grow best as warm-season annuals.

Feeding

None generally required. Plants that show slow growth can be drenched with a dilute liquid organic fertiliser every three weeks.

Spacing

Single Plants: 35cm (1' 1") each way (minimum)
Rows: 35cm (1' 1") with 35cm (1' 1") row gap (minimum)

Sow and Plant

Mexican sunflowers are easily grown from seed started in late spring. Do not rush, because the plants will not grow in cold soil. Expect seeds to germinate within 10 days when sown indoors. Set out seedlings when they are about 6 weeks old. Or, direct-sow seeds where you want the plants to grow in late spring and thin to proper spacing. Crowded seedlings are easy to dig and transplant provided they are watered well. Mexican sunflowers tolerate humid heat well, but they do require steady light moisture. Locate them that is easy to reach with water.
Our Garden Planner can produce a personalized calendar of when to sow, plant and harvest for your area.

Notes

Mexican sunflowers can grow to 1.8m (6 feet) tall, with numerous side branches. Three plants grown as a group resembles are large, summer-blooming shrub. Butterflies and bees love the open blossoms. In warm climates, Mexican sunflower is a modest reseeder.

Harvesting

Gather blossoms to use as cut flowers soon after they open. Snipping off old flowers improves the appearance of these stately plants, and may prolong bloom time. Or, leave the seeds to be harvested by goldfinches.

Planting and Harvesting Calendar

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Pests which Affect Mexican Sunflower

Aphids (General)

Slug

Snail