Sunflower multiflorus

The many-flower sunflower (*Helianthus × multiflorus*) is an artificial hybrid between sunflower species *Helianthus annuus* and *Helianthus decapetalus*, grown as a clumping perennial. Reference plants range from about 3½ to 6 feet tall and around 3 feet wide, with yellow flower heads in late summer; named garden forms vary in flower fullness and vigor. [Kew](https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:119182-2) · [USDA ARS](https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomydetail?id=27933) · [NC State Extension](https://extensiongardener.ces.ncsu.edu/gardening-publications-2/extgardener-previous-newsletters/extgardener-past-features/extgardener-sunflowers-live-up-to-their-namesake/) · [Purdue Extension](https://ag.purdue.edu/department/hla/extension/extension-publications-library/ext-pubs/ho-79-w.html) ## Garden Use Use this perennial in a sunny border or informal group where its late-summer flowers and substantial clump can be seen. A planting width near three feet is a useful guide, though established garden selections may vary. ## Growing Conditions Choose a sunny position and moist but well-drained soil. The RHS notes that *H. multiflorus* does well in moist or damp ground, while NC State Extension describes a sturdy clumping habit and recommends it for a mixed perennial border. ## Maintenance Allow the clump room to develop and remove old stems after flowering or in early spring. Height and flower fullness vary among named garden selections, so leave room for the plant’s mature clump. [RHS growing guide](https://www.rhs.org.uk/plants/helianthus/growing-guide) · [NC State Extension](https://extensiongardener.ces.ncsu.edu/gardening-publications-2/extgardener-previous-newsletters/extgardener-past-features/extgardener-sunflowers-live-up-to-their-namesake/)