Maximilian Sunflower
Helianthus maximiliani
- Native to:
- Canada, Mexico, United States
Jim Pisarowicz
Taxonomy
- Division:
- Magnoliophyta | - Flowering plants
- Family:
- Asteraceae
- Genus:
- Helianthus
- Species:
- Helianthus maximiliani
- USDA Symbol:
- HEMA2
Growth Characteristics
- Life Cycle:
- Perennial
- Growth Habit:
- Forb/herb
- Height:
- 300 cm
- Light Requirements:
- Full Sun
- Drought Tolerance:
- High
- Bloom Months:
- jul,aug,sep,oct
- Bloom Colors:
- yellow
Wildlife Benefits
- Bees:
- ★☆☆☆☆ Documented bee visitation (GBIF)
- Butterflies & Moths:
- ★★☆☆☆ Documented Lepidoptera association (GBIF)
- Caterpillars:
- ★☆☆☆☆ Recorded caterpillar host plant (HOSTS Database)
Keystone Species Ranking
- Caterpillar Keystone:
- ★★★★☆ Butterfly & moth species supported by this genus (NWF)
- Pollen Specialist Bee Keystone:
- ★★★★★ Native pollen specialist bee species supported by this genus (NWF)
Host Plant for Caterpillars
Tischeria helianthi, Bordered Patch (Chlosyne lacinia)
Reported Fauna Sightings
Bees: American bumble (Bombus pensylvanicus), Brown-belted bumble bee (Bombus griseocollis), Hunt's bumble bee (Bombus huntii), Southern plains bumble bee (Bombus fraternus) Butterflies:Atalopedes Scudder, Fiery Skipper (Hylephila phyleus), ⚠️Monarch butterfly (Danaus plexippus)
Garden & Ecology Notes
- Wildlife Value:
- birds, bees, butterflies, small mammals
- Fire Ecology:
- Fire adapted — tolerates or benefits from fire
- Fire Notes:
- Resprouts vigorously from deep rhizomes after fire; historically maintained by prairie fires.
Soil Requirements
- Soil Type:
- well-drained, sandy or loamy soil
- pH:
- 6.0 - 7.5 (slightly acidic to neutral)
- Drainage:
- excellent drainage required
- Moisture:
- dry to moderate
- Notes:
- native to prairies and open fields
Propagation & Germination
- Stratification:
- Cold/moist stratification required — 30–60 days
- Germination Time:
- 10–21 days
- Notes:
- Seeds germinate readily with cold stratification; light may improve germination rates.
The above propagation data sourced from Claude AI
Pre-treatment: Seeds are placed in cold moist stratification for 56 days.
Establishment: H. maximillianii is found from southern Canada to Maine, south to North Carolina and west to the Rocky mountains to Texas. It is introduced elsewhere.
Source: npn.rngr.net
ORGHPS Germination Guide: Expose to fluctuating outdoor winter temps incl. freezing for 3 months. Increase light/temp in spring.