Growing Guide Helianthus (perennial Sunflower)
Growing Helianthus (perennial Sunflower)
Perennial Sunflowers are large plants, 5-8' tall, with 2" single or double, lemon yellow flowers in July-Sept.; zones 4-7s/10w for 'Flore Pleno', 4-9S/10W for 'Lemon Queen'. Roughly hairy stems and leaves. Combine with Heliopsis, Rudbeckia, Helenium, Hemerocallis, Ornamental Grasses.
Suggested use: In the back of the border, or in a meadow.
CULTURE: Full sun; average soil; fertilize seldom as too much will cause more foliar growth and fewer blossoms; water during dry spells; space 24-36"; allow plenty of room; divide every 2-3 yrs.
PROBLEMS: No serious pests or diseases, but mildew can occur in humid regions.