Big Smile
Helianthus annuus
Photo: Kritzolina · Wikimedia Commons · (CC BY-SA 4.0)
Attractive in small beds, containers, and 4-6" pots. 3-6" blooms are bright golden-yellow with a black center. Day neutral. Branching. Bears pollen.
Harvest
50-60d
Days to harvest
Sun
Full sun
Zones
2–11
USDA hardiness
Height
1-10 feet
Planting Timeline
Showing dates for Big Smile in USDA Zone 7
All Zone 7 flower →Zone Map
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Big Smile · Zones 2–11
Growing Details
Zone-by-Zone Planting Calendar
| Zone | Indoor Start | Transplant | Direct Sow | Harvest |
|---|---|---|---|---|
| Zone 1 | May – June | July – August | July – September | — |
| Zone 2 | April – May | June – July | June – August | — |
| Zone 11 | January – January | January – February | January – March | — |
| Zone 12 | January – January | January – February | January – March | — |
| Zone 13 | January – January | January – February | January – March | — |
| Zone 3 | April – May | June – July | June – August | — |
| Zone 4 | March – April | June – June | June – July | — |
| Zone 5 | March – April | May – June | May – July | — |
| Zone 6 | March – April | May – June | May – July | — |
| Zone 7 | February – March | April – May | April – June | — |
| Zone 8 | February – March | April – May | April – June | — |
| Zone 9 | January – February | March – April | March – May | — |
| Zone 10 | January – January | February – March | February – April | — |
Succession Planting
Big Smile runs 50–60 days from direct sow to bloom, which makes succession planting straightforward. Direct sow every 14–21 days starting April 1 through mid-June in zone 7; that gives you continuous flowers from roughly late May into early September. Stop sowing once daytime highs are consistently above 90°F — germination rates drop and seedlings struggle to establish in that heat.
If you want blooms pushing into fall, start one last round indoors in late June and transplant out in mid-July once evenings cool slightly. Don't bother with succession past that point — days are shortening and you won't get full heads before frost shuts things down.
Complete Growing Guide
Big Smile sunflowers are among the easiest flowers to grow, making them ideal for beginning gardeners and children. These compact cultivars typically reach just 18 inches tall, creating perfect specimens for small garden spaces, container displays, and decorative 4-6 inch pots. Starting your Big Smile sunflowers is straightforward—direct sowing is recommended rather than indoor starting, as these plants develop long taproots that don't transplant well. Sow seeds directly into the garden after your last spring frost date, or indoors 3-4 weeks before if you prefer a head start. Plant seeds half an inch deep in warm soil, spacing them 6-12 inches apart depending on your desired density. These sunflowers aren't particularly fussy about soil but perform best in well-draining garden beds or container mix enriched with compost.
Once established, Big Smile sunflowers require minimal maintenance. Water consistently during the first month of growth, then transition to deeper but less frequent watering as the plants mature. The branching habit of this variety means you'll get multiple flower stems per plant, so generous watering encourages abundant blooms. Feed every two weeks with a balanced fertilizer, switching to a phosphorus-rich formula once flowering begins to support the abundant 3-6 inch golden-yellow blooms with characteristic black centers.
The pollen-bearing flowers of Big Smile attract numerous pollinators, which unfortunately can bring along certain pests. Watch carefully for sunflower beetles and stem weevils, which specifically target sunflower varieties at this size; regular inspection allows you to hand-pick insects before infestations develop. Powdery mildew occasionally affects the foliage in humid climates, so ensure good air circulation around plants and avoid overhead watering.
Big Smile's branching tendency is actually its greatest asset, but many gardeners don't take full advantage of it. Pinching back the main stem when plants reach 4-6 inches tall stimulates more lateral branches and significantly increases your flower yield. This simple technique transforms a single stem into a bouquet producer, particularly valuable when growing these sunflowers for cutting. Succession planting every two weeks from spring through early summer ensures continuous blooms throughout the season, since individual plants reach peak flowering around 50 days after sowing.
The one aspect gardeners frequently underestimate is the importance of full sun exposure for Big Smile. While these sunflowers tolerate partial shade better than larger varieties, they genuinely need six to eight hours of direct sun daily to produce the vibrant golden color and sturdy stems that make them attractive. Plants grown in insufficient light become leggy and pale, producing fewer and smaller flowers. Provide consistent full-sun locations for optimal performance, and your Big Smile sunflowers will reward you with cheerful, prolific blooms throughout the season.
Harvesting
Big Smile reaches harvest at 50 - 60 days from sowing per Johnny's Selected Seeds. Expect 4-6" at peak. As an annual, harvest continues until frost ends the season.
Seeds are ovoid and somewhat flattened
Color: Black, Brown/Copper. Type: Achene. Length: < 1 inch. Width: < 1 inch.
Garden value: Edible
Harvest time: Fall
Edibility: Seeds are used for cooking oil, livestock feed, and as a snack food or garnish. Petals are edible and young flower buds can be steamed like artichokes.
Storage & Preservation
Cut Big Smile flowers last 7-10 days in a vase with fresh, cool water changed every 2-3 days. Add a commercial flower preservative (or a homemade mix of sugar, bleach, and citric acid) to extend vase life. Keep cut arrangements away from ripening fruit, direct sunlight, and heating vents, which accelerate wilting.\n\nFor pressed flowers and dried arrangements, hang stems upside-down in a dark, dry location (attic, closet, garage) for 2-3 weeks. Once fully dried, Big Smile retains color reasonably well for dried bouquets or floral crafts.\n\nTo preserve petals for herbal use or crafts, harvest fully open flowers on a dry morning, separate petals, and dry on paper towels or screens in a warm, dark location for 1-2 weeks. Store dried petals in airtight jars away from light. For seed saving, allow mature seed heads to dry completely on the plant, harvest, and store dry seeds in cool (60°F), dry conditions in sealed envelopes or jars for next season.
History & Origin
Big Smile is open-pollinated, meaning seed saved from healthy plants will produce true-to-type offspring. Listed in the Johnny's Selected Seeds catalog.
Origin: Western United States
Advantages
- +Compact size perfect for small spaces and container gardening
- +Quick blooming in just 50-60 days from seed
- +Bright golden-yellow flowers with striking black centers attract pollinators
- +Day-neutral variety blooms reliably regardless of daylight length
- +Branching habit produces multiple flowers per plant
Considerations
- -Pollen-bearing flowers may trigger allergies in sensitive gardeners
- -Black centers can develop powdery mildew in humid conditions
- -3-6 inch blooms are relatively small for cut flower arrangements
Companion Plants
Marigolds are the most practical companion here — they deter aphids and whiteflies through scent, and they pull in predatory insects that will also patrol your sunflowers. Sweet Alyssum does similar work by feeding parasitic wasps with its small, accessible flowers. Nasturtiums are a useful trap crop: Aphis helianthi tends to pile onto them instead of your sunflowers, which concentrates the problem where you can actually deal with it. Zinnias and Cosmos fill out the support cast — more nectar sources, and neither one will fight Big Smile for water or root space at 12–18 inches out.
The harmful companions are worth taking seriously. Black Walnut produces juglone, a compound that disrupts root respiration in Helianthus annuus — give any walnut tree a wide berth, at least 50 feet. Eucalyptus drops allelopathic compounds through its leaf litter that suppress germination and early root development. And planting Big Smile next to other sunflower varieties is a quiet mistake — same species packed together concentrates both Aphis helianthi pressure and powdery mildew risk in one spot.
Plant Together
Marigolds
Repel nematodes and aphids while attracting beneficial insects
Sweet Alyssum
Attracts beneficial insects like hoverflies and parasitic wasps
Nasturtiums
Act as trap crops for aphids and cucumber beetles
Lavender
Repels moths, fleas, and mosquitoes while attracting pollinators
Cosmos
Attracts beneficial insects and provides complementary colors
Zinnias
Attract ladybugs and other beneficial predatory insects
Petunias
Repel aphids, tomato hornworms, and asparagus beetles
Salvia
Attracts pollinators and repels harmful insects with aromatic oils
Keep Apart
Black Walnut
Releases juglone toxin that inhibits growth of many flowering plants
Sunflowers
Compete heavily for nutrients and water, may stunt smaller flowers
Eucalyptus
Produces allelopathic compounds that inhibit germination and growth
Pests & Disease Resistance
Common Pests
Aphids, spider mites, slugs
Diseases
Powdery mildew, downy mildew, rust
Troubleshooting Big Smile
What you'll see, why it happens, and what to do about it.
Leaves covered in white powdery coating, usually starting on upper leaf surfaces around week 4–6
Likely Causes
- Powdery mildew (Erysiphe cichoracearum) — thrives in warm days with cool nights and poor airflow
- Overcrowded planting at less than 12 inches apart
What to Do
- 1.Remove the worst-affected leaves and bin them — don't compost
- 2.Spray with a diluted baking soda solution (1 tablespoon per gallon of water) every 7 days as a stopgap
- 3.Next sowing, hold to 18-inch spacing and don't overhead water in the evening
Sticky residue on stems and leaves, with small clusters of soft-bodied insects on new growth or the backs of leaves
Likely Causes
- Aphid infestation (commonly Aphis helianthi, the sunflower aphid) — populations explode fast in warm weather
- Absence of natural predators, often because nearby plants lack nectar sources
What to Do
- 1.Blast them off with a firm stream of water from a hose — repeat every 2–3 days until numbers drop
- 2.If the colony is established, apply insecticidal soap directly to affected stems and leaf undersides
- 3.Plant Sweet Alyssum or Marigolds within 12 inches to draw in parasitic wasps and ladybugs
Ragged holes chewed into lower leaves or seedling stems cut clean at soil level overnight
Likely Causes
- Slugs — most active after rain or irrigation when soil stays wet past dark
- Young transplants under 3 inches tall are especially vulnerable
What to Do
- 1.Set out shallow traps (a tuna can sunk flush with the soil, filled with cheap beer) near the base of plants — check and empty every morning
- 2.Scatter iron phosphate bait (Sluggo is a common brand, safe around pets) around the planting area
- 3.Let the soil surface dry out between waterings; slugs won't cross dry ground if they can help it
Frequently Asked Questions
How long does it take for Big Smile to bloom from seed?▼
Can you grow Big Smile in containers or pots?▼
Is Big Smile good for beginners?▼
When should I plant Big Smile seeds?▼
How often should I water Big Smile?▼
What does Big Smile look like as a cut flower?▼
Growing Guides from Wind River Greens
Where to Buy Seeds
Sources & References
External authority sources used in compiling this guide.
- BreederJohnny's Selected Seeds
See the Methodology page for how this data is sourced, what's AI-assisted, and known limitations.