Also known as Sunflower · 478 saves
Helianthus
Helianthus, the genus most gardeners know as sunflower. We track 31 varieties; the ones most used by real gardeners.
The 24 most-saved Helianthus varieties
See all 31 Helianthus varieties →Search this genus →
10 species of Helianthus
Each one is a parent of the varieties above.
Track your Helianthus in Sow
Save the Helianthus you grow and get care reminders timed to your zone.
How to grow Helianthus
Whats common across all Helianthus varieties in our catalog — drawn from the care records of the 31 most-grown of them.
The Helianthus year
- PlantApril–June74% of varieties
Sow seeds directly outdoors once the soil has warmed and frost danger has passed.
- StakeJune and July71% of varieties
Stake tall varieties when plants reach 2-3 feet to prevent flopping.
- HarvestAugust–October65% of varieties
Cut for bouquets or leave seed heads to dry for birds.
- FertilizeJune–August32% of varieties
Apply balanced fertilizer once or twice early in the season.
Do
- Water deeply once a week during dry spells 🌱
- Deadhead spent flowers to encourage more blooms
- Water deeply once a week 🌱
- Apply a balanced fertilizer monthly during the growing season
- Deadhead faded flowers to encourage more blooms
Avoid
- Avoid overwatering to prevent root rot ❌
- Avoid overwatering, which can cause root rot ❌
- Do not plant in shady areas, as sun is essential
- Refrain from fertilizing late in the season
What goes wrong with Helianthus
| Problem | What you'll see | What to do |
|---|---|---|
| Aphids | Sticky residue and distorted leaves | Spray with neem oil or insecticidal soap |
| Sunflower beetle | Chewed leaves and defoliation | Use organic insecticidal sprays or handpick beetles |
| Spider mites | Fine webbing and speckled leaves | Use horticultural oil or insecticidal soap |
| Sunflower beetles | Chewed, skeletonized foliage on young leaves and stems. | Handpick beetles from the plants or apply targeted organic controls if damage threatens plant survival. |
| Powdery mildew | White, powdery fungal patches on the upper surfaces of the leaves. | Space plants widely to maximize air circulation and avoid overhead watering. |
| Powdery Mildew | White powder on leaves | Improve air circulation and apply fungicide |
| Downy mildew | Pale green or yellow spots on upper leaf surfaces with fluffy gray growth underneath. | Ensure excellent drainage and remove affected foliage to prevent the spread of spores. |
Making more Helianthus
Seed
- Wait until all danger of spring frost has passed and soil temperatures have warmed.
- Clear the planting area of weeds and loosen the top few inches of sandy or loamy soil.
- Sow seeds directly at a depth of half an inch, spacing them several inches apart.
- Keep the soil lightly moist until germination occurs, then thin seedlings to their final spacing.
Seeds
- Tuck seeds into moist soil in early spring
- Maintain consistent moisture for 2 weeks
- Seeds germinate in 7-10 days
Helianthus questions
How many types of Helianthus are there?
The Sow catalog tracks 31 distinct Helianthus varieties. The most popular — ranked by 478 real gardeners — are shown first above.
What zones does Helianthus grow in?
Across its varieties, Helianthus covers USDA Zones 4–10. Individual varieties differ — each plant page lists its exact range, and Sow filters the catalog to your zone automatically.
When does Helianthus bloom?
Most Helianthus varieties bloom in late summer, late summer to fall, summer to fall. Staggering early, mid, and late varieties extends the genus's season in one bed.
Which Helianthus should I choose?
Start from the most-saved varieties above — popularity across thousands of gardens is a strong signal of reliability — then filter by your zone and sun. In the Sow app you can preview any of them in a photo of your actual yard before you buy.