2 named cultivars
The Story
Plant Bio
Helianthus angustifolius, swamp sunflower, is a tall clumping perennial native to the eastern and southern United States, reaching five to eight feet. Narrow willow-like leaves clothe the stems, and from September into November the plant carries hundreds of two-inch golden daisies with dark centres, flowering when almost everything else has finished.
Despite the name it grows perfectly well in ordinary garden soil, and tolerates salt, poor ground and periodic wet — but it flowers so late that in the coldest parts of its range frost can arrive first. Its height invites flopping, and a hard cut in early summer is the standard remedy.
Uses & Benefits:
Essentials
At a Glance
Plant Type
Perennial
Height
78 inches
Width
39 inches
Light
Full Sun, Partial Sun
Zones
5, 6, 7, 8, 9
Water
Moderate
Humidity
Moderate
Lifespan
Perennial
Native To
Eastern and southern United States
Toxicity
Non-toxic
Marketplace
Where to Buy
Shipping costs Year-round shipping Free shipping
Planting
How to Grow
- Plant in spring in moist to average soil.
- Choose full sun for upright stems.
- Allow three to four feet of width per clump.
- Water through dry spells in the first season.
- Cut back by half in early summer to control height.
- Divide every three years to keep clumps vigorous.
Pro Tip
Cut it back by half in June — it still flowers on time in autumn, at four feet instead of eight, and stops the whole clump collapsing.
Keep It Thriving
Care Guide
Do
- Plant in full sun ☀️
- Cut back by half in early summer ✂️
- Divide every three years 🌱
- Leave seed heads for winter birds 🐦
Don't
- Plant in deep shade, where it flops badly ❌
- Expect flowers before September ❌
- Crowd it; the clump gets substantial ❌
Seasonal Care Calendar
| Task | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Divide | ||||||||||||
| Prune |
Watch Out For
Pests & Diseases
Common Pests
Common Diseases
In the Garden
Landscape Uses & Companions
Landscape Uses
Companion Plants
Multiply
Propagation Methods
Good to Know
Common Questions
Swamp Sunflower questions
What zones can Swamp Sunflower grow in?
Swamp Sunflower is hardy in USDA Zones 5–9. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.
Is Swamp Sunflower deer resistant?
Yes — Swamp Sunflower is rated deer-resistant. Deer typically pass it over, though extreme hunger can override any plant's defenses.
When does Swamp Sunflower bloom?
Swamp Sunflower typically blooms in late summer to fall through early fall. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.
Does Swamp Sunflower need full sun?
Swamp Sunflower does best in full sun to part shade. In hot climates, afternoon shade keeps blooms fresher longer.
Is Swamp Sunflower drought tolerant?
Yes — once established (usually after the first full season), Swamp Sunflower handles dry spells with minimal watering. Water deeply its first year to build the root system that makes that possible.
More Helianthus to compare
Maximilian sunflower
Helianthus maximiliani
Narrow-Leaf Sunflower Low Down
Helianthus angustifolius 'Low Down'
Bolander's Sunflower
Helianthus bolanderi
Salicifolius Sunflower Willowleaf Sunflower
Helianthus salicifolius
Table Mountain Sunflower
Helianthus annuus 'Table Mountain'
Common Sunflower
Helianthus annuus
Keep exploring
Explore the genus
Hardy in your zone?
Grow Swamp Sunflower with confidence
See it in a design of your actual yard, get zone-matched care reminders, and track it season by season in your garden journal.