Helianthus annuus. Lemon Queen Organic sunflower seeds are CERTIFIED ORGANIC! Lemon Queen is a wonderful, medium tall sunflower with brilliant light lemon yellow flowers that are typically 10-13cm (5-6″) wide. with chocolate brown centers. This sunflower develops numerous branches, and each bears multiple flowers. Grow some for cut flowers and enjoy the bright colour indoors. Lemon Queen grows to about 1.8-2m (6-7′) tall. Direct sow sunflower seeds in full sun in well drained soil once it warms up from April to June. Plant more seeds at three week intervals for a much longer bloom period. This sunflower begins flowering about 90 days after sowing.