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Sunflower Companion Planting

Helianthus annuus

Daisy (Asteraceae) -- warm season

2 beneficial companions
2 antagonistic relationships

Good Companions for Sunflower

CucumberCucumis sativus
BeneficialPollinator AttractionSupported

Sunflowers attract pollinators (native bees, honeybees) that improve cucumber fruit set. Tall sunflower stems also serve as trellising support for vining cucumber varieties.

Plant sunflowers on bed borders. Cucurbits depend on insect pollination for fruit set -- any pollinator-attracting companion improves yield.

Sources
  • Pollinator-dependent crop production and the role of wild bees -- Ecological Applications (2011)
  • Insect Pollination of Cucurbits -- University of Florida IFAS Extension (2017)
Sweet CornZea mays
BeneficialPollinator AttractionSupported

Sunflowers on bed borders attract pollinators and predatory insects. They also function as a windbreak, reducing corn lodging in exposed sites. Both are tall warm-season crops with compatible growth habits.

Plant sunflowers on the north side of corn to avoid shading. Use as border or windbreak.

Sources
  • Pollinator-dependent crop production and the role of wild bees -- Ecological Applications (2011)
  • Sunflower border plantings for pollinator habitat -- University of Minnesota Extension (2019)

Crops to Avoid Near Sunflower

PotatoSolanum tuberosum
AntagonisticAllelopathyDocumented

Sunflower (Helianthus annuus) produces allelopathic compounds (chlorogenic acid, scopolin) in decomposing residues and root exudates that inhibit tuber development and reduce potato yield.

Do not follow sunflower with potato in rotation. Keep at separate ends of the garden.

Sources
  • Allelopathic effect of sunflower on succeeding crops -- Allelopathy Journal (2006)
  • Sunflower allelopathy for weed control -- Agronomy for Sustainable Development (2010)
Pole BeanPhaseolus vulgaris
AntagonisticAllelopathySupported

Sunflower allelopathic residues (chlorogenic acid, scopolin) in decomposing leaves and stems inhibit bean seed germination. The effect is strongest in the following season when residues decompose.

Avoid planting beans where sunflower residues are decomposing. Clear sunflower stalks before planting legumes.

Sources
  • Allelopathic effect of sunflower on succeeding crops -- Allelopathy Journal (2006)