Giant Sunflower
Helianthus giganteus
KeystoneBird foodPollinator plant

(c) Homer Edward Price, some rights reserved (CC BY)
Growing it
| Type | wildflower |
|---|---|
| Sun | Full sun, partial shade |
| Water | Medium, high |
| Soil | pH 5.5–7.5 |
| Hardiness | zone 3–8 |
| Mature height | 3 m |
| Mature spread | 0.9 m |
| Spacing | 0.6 m |
| Years to maturity | 1 |
| Bloom | Aug–Sep |
| Flower colour | Yellow not verified |
| In bloom | August September |
| Fruit | Oct |
| Native to | AB, SK |
egg-shaped leaves about 20 cm long in opposite pairs
Documented animals
11 documented relationships.
nectar for
- Agapostemon splendens Specimen records from iNaturalist.org
- American Bumble Bee Specimen records from iNaturalist.org
- Andrena helianthi Specimen records from iNaturalist.org
- Brown-belted Bumble Bee Specimen records from www.bumblebeewatch.org
- Gray Hairstreak Specimen records from iNaturalist.org
- Half-black Bumble Bee Specimen records from iNaturalist.org
- Halictus ligatus Specimen records from iNaturalist.org
- Monarch Specimen records from iNaturalist.org
- Tricoloured Bumble Bee Specimen records from www.bumblebeewatch.org
- Vespula germanica Specimen records from iNaturalist.org
seed for
- American Goldfinch Cornell Lab of Ornithology
Where it has been recorded
- Prairies : from the catalogue's regional tag, not from occurrence records
A range seen three times is not the same claim as one seen three hundred, so the count travels with the region. Boundaries digitised from the National Ecological Framework for Canada v2.2 (Ecological Stratification Working Group 1995), simplified to about 900 m for display: an outline is accurate to roughly a kilometre, not to the metre.
Also worth knowing
Safety
Toxicity not assessed, absence of a warning is not a guarantee of safety
Edible parts
Seeds
Buying it
price: about $8–$16 per plant (estimate); availability: native specialist; notes: Estimate (herb default); AB retail as of 2026
Where these numbers came from
- Flower detail: not verified, a genus-level estimate