Sunflower Fir0002 / GFDL 1.2
garden

Sunflower

Helianthus ×ambiguus

Overview

Towering symbols of summer joy, sunflowers have been cultivated by Native Americans for over 4,500 years — one of the few crops domesticated in North America. Their massive flower heads track the sun (heliotropism) when young, and a single head can contain up to 2,000 seeds. Beyond the classic giant yellow, modern varieties come in burgundy, bicolor, and branching multi-flower types.

Growing Conditions

Hardiness Zones5 — 9
Height2.38m
Spread0.7m
Growth HabitForb/herb
Pollinator Valuehigh

Companion Planting & Soil

Good Companions

CornSquashCucumberLettuceBean

Avoid Planting Near

Potato
Soil pH6 — 7.5
Soil TypeAverage, well-drained soil; drought-tolerant once established

Planting Calendar

When to sow, transplant, and harvest by growing zone.

ZoneActionMonthsNotes
Cold (1-2) Direct Sow Jun — Jun Direct sow after last frost; 1" deep
Cold (1-2) Harvest Aug — Sep Harvest when back of head turns brown
Cool (3-4) Direct Sow May — Jun Direct sow after last frost
Cool (3-4) Harvest Aug — Sep Harvest when back of head turns brown
Moderate (5-7) Direct Sow Apr — Jun Direct sow; succession sow every 2 weeks
Moderate (5-7) Harvest Jul — Oct Harvest when seeds are plump
Warm (8-9) Direct Sow Mar — May Direct sow in spring
Warm (8-9) Harvest Jun — Aug Harvest before birds get them
Hot (10+) Direct Sow Feb — Apr Direct sow early; avoid summer heat
Hot (10+) Harvest May — Jul Harvest before summer heat

Uses

Culinary

  • Seeds roasted and salted for snacking
  • Cold-pressed sunflower oil for cooking
  • Sprouted seeds (microgreens) for salads

Medicinal

  • Seeds rich in vitamin E, selenium, and magnesium
  • Linoleic acid supports skin and cardiovascular health
  • Traditional use of petals as a fever-reducing tea

Other Uses

  • Phytoremediation — sunflowers absorb heavy metals from contaminated soil
  • Dramatic cut flower and garden focal point
  • Bird food from mature seed heads left standing