iva xanthiifolia plants cyclachaena xanthiifolia, giant sumpweed, marsh-elder

agriculture allergen allergy background beautiful bloom blossom botanical bright closeup cluster cyclachaena ecology environment field flora floral garden giant green group grow herb herbaceous iva landscape leaf macro marshelder natural nature outdoor outside park plant plants poison pollen season stem summer summertime sumpweed sunflower thicket toxic vegetation vibrant weed xanthiifolia