Heliopsis helianthoides Seeds | False Sunflower
LATIN NAME: Heliopsis helianthoides
COMMON NAME: False Sunflower
Plant Profile
False sunflower is a clump-forming perennial of the tall-grass prairie, one to one and a half metres tall, with rough, oval leaves and a long succession of golden-yellow daisies from June to September. The flower heads are about six centimetres across, with a raised yellow centre that darkens as it ages, and unlike the true sunflowers the ray florets are fertile and the plant sets seed freely.
The stems are stiff and upright and rarely need staking, and the whole plant is coarse and vigorous in a way that suits a wild planting but not a tight border. It is native to eastern North America, from Ontario to Georgia, and it was in European gardens by 1750. Sommersonne, sold as Summer Sun, is the common garden form, and it is shorter and denser than the wild plant.
Science & Biotechnology
Heliopsis sits in the tribe Heliantheae, the same group as the sunflowers, but it differs in a detail that matters to botanists: the ray florets are female and fertile, while in Helianthus they are sterile or absent. The genus is New World, with about a dozen species running from Canada to Mexico, and Heliopsis helianthoides is the only one in general cultivation.
A Mexican relative, Heliopsis longipes, is the source of affinin, an alkamide that produces a numbing, tingling sensation in the mouth and is used in that region as a remedy for toothache. It belongs to the same compound family that gives the toothache plant its effect, though the prairie plant contains far less of it. The species is a prairie plant in the strict sense, and its seed is included in most tall-grass restoration mixes.
Uses & Benefits
False sunflower is planted for its long season: it starts in June, when the early perennials are finished, and carries on into September, which is more than most yellow daisies manage. It is a plant for a meadow strip, a prairie planting or the back of a big border, and it holds up in wind better than Helianthus.
The flowers are visited by bees, hoverflies and butterflies, and the seeds are taken by goldfinches in autumn. It is also useful as a cut flower, though the stems are short-lived in water. Named forms include Sommersonne, Asahi with semi-double heads, and Prairie Sunset with purple-tinged stems and foliage. The plant is not edible and has no medicinal use in Western practice; its value is entirely ornamental and ecological.
Growing from Seed
Sow in late winter or early spring at 18-21 °C; the seed needs light, so press it into the surface of the compost and do not cover it. Germination takes two to three weeks. The seedlings are vigorous and should be pricked out early, then grown on cool to keep them from stretching.
Plant out in spring after the last frost, 45 centimetres apart, in any soil in full sun; rich soil makes the plants tall and floppy, so lean ground is better. Water for the first season and then leave them alone. Divide the clumps every three years in spring to keep them vigorous, and cut the stems to the ground in late winter rather than autumn, so that the seed heads stand for the birds through the cold months.
Our Take
A dependable yellow daisy for the gap between June and September, and one that stands up without staking. Lean soil keeps it compact.
Related Reading
Gardeners who grow False Sunflower often pair it with these related subjects: