Giant coneflower
Rudbeckia maxima · Asteraceae
Enormous, paddle-shaped, powder-blue leaves form a clump at the base, and bare stems rise to head height carrying yellow daisies with very tall, dark cones.
- Size
- 6 ft tall, 2½ ft wide
- Zones
- 4 to 9
- Light
- Full sun
- Flowers
- Late June to early August
- Pets
- No toxicity recorded
- Job in a bed
- Accent
A bed built around giant coneflower
The planner designed this bed around giant coneflower when this page was made: a 12 × 6 ft (3.7 × 1.8 m) naturalistic planting in zone 6, full sun. It chose the other plants from the 966 that suit those conditions, and says below why giant coneflower stands where it does.
The plants
- 1 Giant coneflower × 3, yellow
- 2 Winter heath × 5, pink
- 3 Leadwort × 12, blue
- 4 Little bluestem 'The Blues' × 4, tan
- 5 Silver sage × 1, silver leaves
- 6 False sunflower 'Summer Nights' × 3, yellow
- 7 Ornamental onion 'Purple Sensation' × 4, purple
- 8 Daffodil × 12, yellow
Why this plant
- Nothing here is unique to it. Its leaf, flower shape and colour are all on the plan already. Its case rests on where it stands and when it performs.
Why here
- Anchors a back corner. At 6 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 little bluestem 'The Blues' (3 ft): no two neighbours there are the same height, so the back steps up and down like a skyline.
- 3 plants in one clump. A single spire is too slight to hold a place alone, so here the accent is a clump.
Why now
- In flower for six weeks. From late June to early August.
- Part of the bed's peak. With leadwort and false sunflower 'Summer Nights' in early August: 3 kinds at once. No week has more.
Planned as a naturalistic planting: low grasses and groundcovers, the matrix, make up 55% of the planted ground. The front edge is finished with silver sage, winter heath and leadwort. Cool colours (pink, blue and purple) set against hot ones (yellow), with tan to calm things between them.
The planner's own design check: 11 Excellent, 5 Good, 1 Satisfactory. It flags one thing to watch: Nothing on this plan is highly poisonous or an aggressive spreader.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where giant coneflower goes in a border
At 6 ft it belongs at the back of a bed. In the planner's ten height classes it is very tall (5 to 6½ ft). It is airy enough to see through, so it can also come forward and veil what is behind it.
Its job: accent. An upright plant used singly, like a punctuation mark, and repeated at intervals to give the bed rhythm.
Worth growing for the cabbage-blue leaves alone. The flower stems are bare, so you look through them, and it can stand near the front in spite of its height.
- Bold, blue foliage in sun
- A see-through vertical accent
- Seed heads for goldfinches
What to plant with giant coneflower
Plants recorded as good partners for it, and what each pairing does:
- Switchgrass 'Shenandoah': its green leaves are a setting for the flowers, before and after; fine leaves against its bold ones.
- Purple coneflower: purple against yellow, opposite each other on the colour wheel, if you choose those colours, in flower together for six weeks; medium leaves against its bold ones; low enough (3 ft) to stand in front of it.
- Russian sage: in flower together for four weeks, from mid July; fine leaves against its bold ones.
Questions about giant coneflower
Does giant coneflower need sun or shade?
Giant coneflower grows in full sun (6 or more hours of direct sun a day).
It wants ordinary well-drained soil, of average fertility, and a good soak in dry spells. Once settled in, it stands drought.
What zones does giant coneflower grow in?
USDA zones 4 to 9. It is hardy to zone 4, which means it survives winter nights down to about −20 °F (−29 °C).
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
When does giant coneflower flower in my zone?
In zone 5 it flowers late June to early August. As a summer flower it moves about half a week for every zone: earlier where it is warmer.
| Zone 4 | Early July to early August |
|---|---|
| Zone 5 | Late June to early August |
| Zone 6 | Late June to early August |
| Zone 7 | Late June to late July |
| Zone 8 | Late June to late July |
| Zone 9 | Mid June to mid July |
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 giant coneflower 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 2½ ft (75 cm), so a group knits into one patch.
It grows 6 ft (180 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many giant coneflower 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 one at a time, repeated along the bed at intervals; a slender one reads better as a clump of three.
In the bed above, the planner used three in one group.
Is giant coneflower 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 giant coneflower?
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.
What flowers after giant coneflower?
Giant coneflower is over by early August. These start as it finishes and carry the same spot on, so it never goes flat:
- Hardy hibiscus: from late July to mid September, 5 ft tall.
- Tiger lily: from late July to late August, 4 ft tall, to stand in front of it and cover its fading stems.
- Little bluestem 'Standing Ovation': from early August to mid September, 3½ ft tall, to stand in front of it and cover its fading stems.
What does giant coneflower look like in winter?
Giant coneflower holds some of its leaves into winter, more in a mild year or a sheltered spot, and they look tired by March. Cut the old ones off as new growth starts.
Is giant coneflower good for bees and butterflies?
Giant coneflower is visited by pollinators, bees, butterflies and songbirds.
It is a host plant: the caterpillars of wavy-lined emerald 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.
More Rudbeckia
- Black-eyed Susan Rudbeckia fulgida
- Black-eyed Susan 'American Gold Rush' Rudbeckia 'American Gold Rush'
- Black-eyed Susan 'Goldsturm' Rudbeckia fulgida var. sullivantii 'Goldsturm'
- Black-eyed Susan 'Little Goldstar' Rudbeckia fulgida var. sullivantii 'Little Goldstar'
- Brown-eyed Susan Rudbeckia triloba
- Coneflower 'Herbstsonne' Rudbeckia 'Herbstsonne'
- Cutleaf coneflower Rudbeckia laciniata
- Gloriosa daisy Rudbeckia hirta
- Gloriosa daisy 'Indian Summer' Rudbeckia hirta 'Indian Summer'
- Sweet coneflower 'Henry Eilers' Rudbeckia subtomentosa 'Henry Eilers'
In these guides
- Deer-resistant perennials for full sun
- Drought-tolerant perennials for full sun
- Pet-safe plants for a sunny border
- Native perennials for pollinators
- 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 wavy-lined emerald
Zone guides: Zone 4 · Zone 5 · Zone 6 · Zone 7 · Zone 8 · Zone 9
Every fact on record
- Type
- Perennial
- Size
- 6 ft (180 cm) tall, 2½ ft (75 cm) wide
- Plant
- 24 in (60 cm) apart
- Height class
- Very tall (5 to 6½ ft)
- Place in the bed
- Back, or further forward: it is airy enough to see through
- Flowers
- Late June to early August; daisies; yellow
- Leaves
- Bold texture, semi-evergreen; blue-green
- Shape
- Upright, clumping
- Hardy in
- USDA zones 4 to 9
- Light
- Full sun
- Soil
- Average, well-drained
- Water
- Moderate
- Feeding
- Light, in spring
- Family
- Asteraceae
- Comes from
- Central and southern United States
- Attracts
- Pollinators, bees, butterflies, songbirds
- Host plant for
- Wavy-lined emerald
- Stands up to
- Deer, drought, heat
Checked against NC State Extension. 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.