Mexican Sunflower Growing Guide
Crop Rotation Group
Fertile, well-drained soil enriched with plenty of compost.
No. Mexican sunflowers grow best as warm-season annuals.
None generally required. Plants that show slow growth can be drenched with a dilute liquid organic fertilizer every three weeks.
Single Plants: 1' 1" (35cm) each way (minimum)
Rows: 1' 1" (35cm) with 1' 1" (35cm) 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.
Mexican sunflowers can grow to 6 feet (1.8 m) 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.
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.
Summer storms can topple the big plants, which benefit from staking.
Planting and Harvesting Calendar
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Pests which Affect Mexican Sunflower