Sunflower

Helianthus annuus · Flower

A cheerful, fast-growing annual that is easy even for children. Giant types can top 10 ft, while branching kinds give many smaller blooms for cutting. Seeds left on the head feed birds in autumn.

💧WaterDeeply once or twice a week (estimated)

☀️LightFull sun, 6–8+ hours

🐾PetsNot toxic

Care at a glance

Light: Full sun, 6–8+ hours
Water: About 1 in per week; deep watering
Soil: Most well-drained soils, pH 6.0–7.5
Temperature: Best 70–80 °F; seedlings handle light cold
Spacing: 6 in for dwarf, 18–24 in for giants
Container: At least 3 gallons for dwarf varieties
Bloom: Blooms 70–100 days from sowing (estimated)
Lifespan: Annual

When?

Sow outdoors after the last frost once soil reaches about 55 °F. Repeat every 2–3 weeks until early summer for a longer show (estimated).

Step by step

Sow seeds 1 in deep where they will grow; they dislike transplanting.
Expect sprouts in 7–10 days; protect from birds with netting at first.
Thin to the final spacing once seedlings have two true leaves.
Water deeply around the root zone, especially once buds form.
Stake giant varieties in windy spots.
Cut branching types often to get more flowers.
For seeds, wait until the back of the head turns yellow-brown, then cut and dry.

Common problems

Seedlings vanish overnightBirds, slugs or rodents; cover until plants are 4 in tall.

Stems bend or snapWind or shallow roots; stake and earth up the base.

Gray-white patches on leavesPowdery mildew late in season; usually harmless, remove worst leaves.

Pets

Not listed as toxic to cats or dogs. If in doubt, ask your vet.

Similar plants

Marigold Pumpkin Zucchini

Sources

ASPCA — Toxic and Non-Toxic Plants

This page is general guidance; no pesticide doses are given.