Heliopsis helianthoides is a mouthful, but it basically means sunflower-like. (Helios was the Greek sun god.) And that's what these plants are. Although similar in looks, Heliopsis helianthoides is not the same as the perennial sunflower in the genus, and consequently it's been given the common name of false sunflower.
Also known as oxeye sunflowers, false sunflowers are easy-growing herbaceous perennial plants that naturalize in grasslands and at the edge of woodlands. They are a native wildflower in a large portion of North America—everywhere except for the western third of the continent. In the garden, they're best started in the spring or fall, and they grow fairly quickly but likely won't bloom in their first year. False sunflowers feature triangular-shaped leaves and branching stems that allow the plants to grow in a bushy habit. The double or single daisy-like, yellow-orange flowers surround a cone-shaped, golden-brown center disk.
|Botanical Name||Heliopsis helianthoides|
|Common Name||False sunflower, oxeye sunflower|
|Plant Type||Herbaceous perennial|
|Mature Size||3 to 6 feet tall and 2 to 3 feet wide|
|Sun Exposure||Full sun|
|Soil Type||Average, dry to medium moisture, well-draining|
|Soil pH||6 to 8|
|Bloom Time||June to August|
|Hardiness Zones||3 to 9|
|Native Area||North America|
How to Grow False Sunflowers
You can start false sunflowers by seed in either the spring or fall. For spring, start seeds indoors four to six weeks before your last frost date. In the fall, you can start seeds in flats or direct sow in mid- to late August. As perennials, they tend to begin blooming in their second year, so a spring seedling might not flower the year it's planted. However, seeds started in the fall should provide blooms the following summer.
This is a reliable repeat bloomer, and you should have flowers from summer into fall. Deadheading (removing spent blooms) will help to keep new buds forming and give the plant a tidier appearance. Plus, false sunflowers make lovely cut flowers and are very attractive to hummingbirds, bees, and butterflies.
False sunflowers are clump-forming and tend to stay in one place, rather than spreading throughout the garden. Dividing your plants every two to three years will keep the clumps from dying in the center. You can do this in either the spring or fall. Moreover, many varieties can get top-heavy and require staking. You also can prune or pinch them back in mid-spring for a shorter, sturdier plant. However, doing this will delay blooming for a couple of weeks.
These plants prefer full sun to grow and bloom their best. They can tolerate light shade, though blooming might not be as vigorous and the stems might be floppy and require support. Plus, they can get leggy if they don't get at least four to five hours of sun per day.
False sunflowers can thrive in a variety of soil types. They can even tolerate dry, poor, rocky, sandy, and clay soils. However, they prefer average, well-draining soil with a neutral soil pH for optimal growth.
Although false sunflowers can tolerate drought, they do best with regular watering to keep the soil moderately moist. So if you've had a stretch without rainfall and the soil is dry, be sure to water your plants.
Temperature and Humidity
False sunflowers are cold-hardy perennials that will come back year after year in northern climates up to USDA growing zone 3. Some varieties also have good heat tolerance, making them ideal for the southern end of the plant's growing zones. These plants also aren't overly picky about humidity.
You likely won't have to fertilize your plants unless you have very poor soil. Rich soil can cause a lot of leggy stem growth on false sunflowers. So go easy on the organic matter and fertilizer.
Common Pests and Diseases
In general, false sunflowers don't have any serious pest or disease issues. But aphids can be a problem for the plants, as can powdery mildew. With aphids, you might notice crumpled or otherwise damaged foliage. And with powdery mildew, you’ll see splotches of white or gray on the leaves and stems. Providing good air circulation for your plants can help to prevent and mitigate both of these issues before you turn to insecticides or fungicides.
Varieties of False Sunflowers
You will be hard-pressed to find a bad false sunflower. Most varieties are easy to grow and bloom reliably. They include:
- 'Asahi': Midsized plant with fluffy double flowers
- 'Loraine Sunshine': Early bloomer with variegated leaves
- 'Prairie Sunset': Tall plant with dark purple stems
- 'Summer Nights': Plant with dark red stems, red-tinged foliage, and gold flowers with mahogany centers
- 'Summer Sun': Tall plant with lots of semi-double golden flowers