https://pfaf.org/User/Plant.aspx?LatinName=Helianthus+giganteus
Helianthus giganteus is a PERENNIAL growing to 3.6 m (11ft 10in) at a fast rate. See above for USDA hardiness. It is hardy to UK zone 4. It is in flower from...
helianthus giganteusgiant sunflowerplant databasepfaf