Woodland sunflower
Helianthus divaricatus · Asteraceae
Bright yellow daisies on slender stems with paired, stalkless leaves, in the dry shade at the edge of a wood, from midsummer.
- Size
- 4 ft tall, 3 ft wide
- Zones
- 3 to 8
- Light
- Part sun to part shade
- Flowers
- Mid July to early September
- Pets
- No toxicity recorded
- Job in a bed
- Drift
A bed built around woodland sunflower
The planner designed this bed around woodland sunflower when this page was made: a 12 × 6 ft (3.7 × 1.8 m) naturalistic planting in zone 6, part sun. It chose the other plants from the 341 that suit those conditions and its dry soil, and says below why woodland sunflower stands where it does.
The plants
- 1 Woodland sunflower × 3, yellow
- 2 Mountain sandwort × 19, white
- 3 October daphne × 8, pink
- 4 Purple milkweed × 3, purple
- 5 Dwarf English boxwood × 1, dark green leaves
- 6 Wood spurge × 3, green
- 7 Meadow saffron × 3, pink
- 8 Grecian windflower × 8, blue
Why this plant
- The only yellow. The one hot colour: every other flower here is cool or neutral.
Why here
- Anchors a back corner. At 4 ft it is the tallest plant here, and the tallest close the ends of the bed, where they stand in front of nothing.
- A step in the back row. Next to wood spurge (20 in): no two neighbours there are the same height, so the back steps up and down like a skyline.
- 3 plants in one group. Massed, one kind reads as a single shape. Scattered, it would look spotty.
Why now
- In flower for 9 weeks. From mid July to early September.
- Fills a gap. For 8 of those weeks nothing else on the plan is in flower.
Planned as a naturalistic planting: low grasses and groundcovers, the matrix, make up 47% of the planted ground. Woodland sunflower and purple milkweed anchor the back corners of the bed: the tallest plants on the plan stand there. Mountain sandwort repeats along the bed to tie it together.
The planner's own design check: 11 Excellent, 5 Good, 1 Satisfactory. It flags one thing to watch: Meadow saffron is highly poisonous to people, dogs, cats and horses. Woodland sunflower spreads aggressively.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where woodland sunflower goes in a border
At 4 ft it belongs at the back of a bed. In the planner's ten height classes it is moderately tall (3 to 4 ft).
Its job: drift. Planted in a small group of three or five, and repeated further along in the other number.
One of very few sunflowers for shade, and valuable under oaks. It runs strongly underground, so plant it where a colony is welcome.
- Dry shade at a woodland edge
- Native planting under oaks
- Birds and pollinators
What to plant with woodland sunflower
Plants recorded as good partners for it, and what each pairing does:
- White wood aster: in flower together for three weeks, from late August; low enough (24 in) to stand in front of it.
- Blue-stemmed goldenrod.
- Pennsylvania sedge: its green leaves are a setting for the flowers, before and after; low enough (8 in) to stand in front of it.
Questions about woodland sunflower
Does woodland sunflower need sun or shade?
Woodland sunflower grows in part sun (4 to 6 hours of sun, including some afternoon sun) and part shade (2 to 4 hours of sun, mostly in the morning).
It wants dry, sharply drained soil, of average fertility, and little watering once settled. Once settled in, it stands drought.
What zones does woodland sunflower grow in?
USDA zones 3 to 8. It is hardy to zone 3, which means it survives winter nights down to about −30 °F (−34 °C).
Above zone 8 it struggles: the zones measure winter cold, but a plant's top zone usually means the summers are too hot or the winters too mild for it to rest.
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
When does woodland sunflower flower in my zone?
In zone 5 it flowers mid July to early September. As a summer flower it moves about half a week for every zone: earlier where it is warmer.
| Zone 3 | Mid July to early September |
|---|---|
| Zone 4 | Mid July to early September |
| Zone 5 | Mid July to early September |
| Zone 6 | Mid July to early September |
| Zone 7 | Early July to early September |
| Zone 8 | Early July to early September |
Worked out from Hopkins' bioclimatic law: spring arrives about four days later for each degree of latitude north, and one zone is roughly two degrees. A warm spring or a cold one moves any garden two weeks either way.
How far apart should woodland sunflower be planted?
24 in (60 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 3 ft (90 cm), so a group knits into one patch.
It grows 4 ft (120 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many woodland sunflower plants do I need?
At 24 in apart, set out in staggered rows:
- 3 to fill 10 square feet (about 1 m²)
- 6 for a single row 10 ft (3 m) long
- 10 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as a group of three or five, with a second group further along in the other number.
In the bed above, the planner used three in one group.
Is woodland sunflower poisonous to dogs and cats?
No toxicity is recorded for dogs, cats, horses or people, according to NC State Extension.
"Not toxic" is not "edible": a pet that eats a lot of any plant can be sick.
Do deer eat woodland sunflower?
Mostly not. NC State lists it as resistant to deer. No plant is proof against a hungry deer in a hard winter, but this one is low on the menu.
Will woodland sunflower spread?
It spreads sideways, by runners or roots; the risk of it taking over is high. Spreads aggressively by underground stems into large colonies. Use it only where it has room to roam.
What flowers after woodland sunflower?
Woodland sunflower is over by early September. These start as it finishes and carry the same spot on, so it never goes flat:
- Blue-stemmed goldenrod: from early September to mid October, 2½ ft tall, to stand in front of it and cover its fading stems (a recorded partner).
- Blue wood aster: from mid September to mid October, 3 ft tall, to stand in front of it and cover its fading stems.
- White snakeroot: from late August to mid October, 3½ ft tall.
What does woodland sunflower look like in winter?
Woodland sunflower dies down, but leave the stems standing: the seed heads stand through the winter, and songbirds eat the seed. Cut them down in early spring, before the new shoots come.
Is woodland sunflower good for bees and butterflies?
Woodland sunflower is visited by pollinators, specialist bees, butterflies and songbirds.
It is a host plant: the caterpillars of silvery checkerspot feed on its leaves. A butterfly can only lay its eggs on its host plants, so these do more for it than any nectar flower.
It is native to the United States and Canada.
More Helianthus
- Double perennial sunflower Helianthus x multiflorus 'Flore Pleno'
- Maximilian sunflower Helianthus maximiliani
- Sunflower 'Lemon Queen' Helianthus 'Lemon Queen'
- Swamp sunflower Helianthus angustifolius
- Willowleaf sunflower 'First Light' Helianthus salicifolius 'First Light'
In these guides
- Plants for dry shade
- Salt-tolerant plants for roadsides and coasts
- Deer-resistant plants for shade
- Pet-safe plants for shade
- Native perennials for pollinators
- Native plants for shade
- Garden plants native to Canada
- Plants for butterflies
- Plants for bees
- Plants that feed garden birds
- Tall perennials and grasses for the back of a border
- Host plants for the silvery checkerspot
Zone guides: Zone 3 · Zone 4 · Zone 5 · Zone 6 · Zone 7 · Zone 8
Every fact on record
- Type
- Perennial
- Size
- 4 ft (120 cm) tall, 3 ft (90 cm) wide
- Plant
- 24 in (60 cm) apart
- Height class
- Moderately tall (3 to 4 ft)
- Place in the bed
- Back
- Flowers
- Mid July to early September; daisies; yellow
- Leaves
- Medium texture, herbaceous; green
- Shape
- Upright, spreading
- Hardy in
- USDA zones 3 to 8
- Light
- Part sun, part shade
- Soil
- Average, dry and sharply drained
- Water
- Low
- Feeding
- None needed
- Family
- Asteraceae
- Comes from
- Southeastern Canada & the North Central to Eastern United States
- Attracts
- Pollinators, specialist bees, butterflies, songbirds
- Host plant for
- Silvery checkerspot
- Stands up to
- Deer, drought, salt
Checked against NC State Extension and VASCAN (plants of Canada). Flowering times are for zone 5: later in colder zones, earlier in warmer ones. Toxicity and spread information is a general gardening guide, not veterinary or medical advice, and invasive status varies by region. If a person or pet eats a plant, contact poison control or a vet. Check your local invasive species list before planting anything with a spread warning.