Maximilian sunflower Helianthus maximiliani
Maximilian sunflower (Helianthus maximiliani) is a deciduous perennial flowering plant in the Asteraceae family, native to Great Plains of central North America. It grows 1.5–3 m (4.9–10 ft) tall and 60 cm–1.2 m (24 in–3.9 ft) wide, wants full sun and low water, and is hardy to about -35 °C (-31 °F). Space plants about 90 cm (35 in) apart.
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Maximilian sunflower at a glance
| Type | Perennial flowering plant, deciduous |
|---|---|
| Family | Asteraceae |
| Mature height | 1.5–3 m (4.9–10 ft) |
| Mature spread | 60 cm–1.2 m (24 in–3.9 ft) |
| Spacing | 90 cm (35 in) centre to centre |
| Sun | Full sun, at least 7 h of direct sun a day |
| Water | Low; drought tolerance high, waterlogging tolerance none |
| Soil pH | 6–8.5 |
| Cold hardiness | About -35 °C (-31 °F) once established (roughly USDA zone 3) |
| Heat stress | Likely above about 40 °C (104 °F) |
| Flowering | from about August for 4–7 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | Low |
| Pollinator value | High |
| Edible | Yes: seeds (roasted), tubers (cooked, traditionally) |
| Native to | Great Plains of central North America |
| Common in gardens of | 🇺🇸 United States, 🇨🇦 Canada, 🇲🇽 Mexico |
Is Maximilian sunflower toxic?
- People: not known to be toxic
- Cats: not known to be toxic
- Dogs: not known to be toxic
Not poisonous.
If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.
Companion planting: what to grow with Maximilian sunflower
No well-documented helpful pairing. Group it with plants that like full sun and low water.
Questions about Maximilian sunflower
- How far apart should I plant Maximilian sunflower?
- About 90 cm (35 in) apart, centre to centre. A mature plant spreads 60 cm–1.2 m (24 in–3.9 ft).
- Does Maximilian sunflower need full sun?
- Full sun: at least 7 hours of direct sun a day.
- How much water does Maximilian sunflower need?
- Low water. Drought tolerance is high and waterlogging tolerance none.
- How cold-hardy is Maximilian sunflower?
- It tolerates about -35 °C (-31 °F) once established, roughly USDA zone 3.
- When does Maximilian sunflower flower?
- From about August for 4–7 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Maximilian sunflower poisonous to cats and dogs?
- For cats it is not known to be toxic; for dogs not known to be toxic; for people not known to be toxic. Not poisonous.
- What grows well with Maximilian sunflower?
- There is no well-documented companion pairing for Maximilian sunflower. Group it with plants that like the same sun (full sun) and water (low).
Sources and evidence
Evidence grade A (A: strong evidence).
- Plants of the World Online (taxonomy, native range), Royal Botanic Gardens, Kew
- Missouri Botanical Garden Plant Finder, Missouri Botanical Garden
- Native Plant Information Network, Lady Bird Johnson Wildflower Center, University of Texas at Austin
Notes and assumptions
- A tallgrass prairie plant: deep roots make it drought-proof once established; it wants sun and lean soil (rich soil makes it flop). Leave the stems standing in winter for seed-eating birds and overwintering insects.
- Tall stems clothed with folded, arching leaves and lined in autumn with many golden sunflowers, the seeds a feast for finches. Spreads by rhizomes to form big stands. Named after Prince Maximilian of Wied, who explored the Missouri River in the 1830s.
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
Related plants
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- Sunflower Helianthus annuus
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- Zinnia Zinnia elegans
- Cosmos Cosmos bipinnatus
- Purple coneflower Echinacea purpurea
- Black-eyed Susan Rudbeckia hirta
- French tarragon Artemisia dracunculus