The false sunflower (Heliopsis helianthoides), also known as oxeye sunflower, is an easy-growing herbaceous perennial plant that naturalizes in grasslands and at the edge of woodlands. The botanical name of 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.
False sunflowers 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 upright clumps, 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. These plants are not invasive or toxic, so they are friendly to both your garden beds and pets.
|Common Name||False sunflower, oxeye sunflower|
|Botanical Name||Heliopsis helianthoides|
|Plant Type||Herbaceous, perennial|
|Mature Size||3-6 ft. tall, 2-3 ft. wide|
|Soil Type||Moist but well-drained, loamy|
|Soil pH||Acidic, neutral, alkaline|
|Flower Color||Yellow, orange|
|Hardiness Zones||3-9 (USDA)|
|Native Area||North America|
False Sunflower Care
False sunflowers are fairly easy to care for and are clump-forming so do not spread except by seed. This is a reliable repeat bloomer, and you should have flowers for 6 to 8 weeks, from summer into fall. Deadheading (removing spent blooms) will help to keep new buds forming and give the plant a tidier appearance. 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 are great for border plants and brighten up any garden bed with their bright yellowish orange blooms. Plus, false sunflowers make lovely cut flowers and are very attractive to hummingbirds, bees, and butterflies. It is also a deer-resistant plant.
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.
Types 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
False sunflowers do well when pruned. In the spring, to get those nice, fully formed plants, pinch the tips off the ends of the stems on the plant to encourage them to branch out. As false sunflowers bloom, deadhead any flowers that are spent, which will help stimulate new buds to form. If the plants start looking leggy or too tall, trim them back in the early summertime, which also helps produce new flowers. In mid fall, after the false sunflowers have stopped blooming, plan to prune the plants to about 2 inches tall. Pruning can also wait and be done in the early spring after any threat of frost is done.
Propagating False Sunflowers
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. Here's how:
- Select the plant to be divided and using a spade or shovel, dig up the plant making sure to dig deep enough not to disturb the root ball.
- Any dead, mushy, or broken roots should be cut off the root ball with pruning shears before separating the plant.
- Using a sharp knife cut the plant apart in half or thirds.
- Plant the divided plants immediately in a prepared suitable location and water the soil till moist but not overwet.
How to Grow False Sunflowers From Seed
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, direct sow in mid-to-late August. Keep the growing medium moist but not overwet. If started indoors, the seedlings can be planted outside once any danger of frost has passed. Make sure to harden off seedlings before planting outside. Sowing directly into the garden will require being planted in moist but well-drained soil and covering with about 1/8 inch of dirt. Water and plan to thin the seedlings as needed. Plants should be spaced 18-24 inches apart.
As perennials, false sunflowers 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.
Potting and Repotting False Sunflowers
Since false sunflowers grow in clumps, they work well for putting in pots or container beds with other flowers. Place them in a container with potting soil, making sure to plant to the same depth, not covering up the base of the plant. Full sun and plenty of water will keep these adorning your patio or lanai, creating a colorful and beautiful arrangement.
False sunflowers that are planted in the ground can be left untrimmed until spring. The dead leaves and stems will help to protect the roots and base of the plant, plus wild birds will feed on any remaining seeds. Plants that are in containers can be brought in to a garage area or placed in a protected location and elevated to avoid ground frost.
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. A strong spray of water may remove aphids.
How to Get False Sunflowers to Bloom
These bright, cheery flowers love to bloom and will start flowering in early July and go through August. To keep false sunflowers blooming longer, simply take off any flowers that are done blooming by deadheading them. This process not only keeps the plants looking fresh and neat, but also encourages more flowers. Trimming the plants if they get too tall or look scraggly will also encourage further flowering.
How long do false sunflowers live?
False sunflowers come back every year, but these flowers typically have a lifespan of around five years. They can self-propagate by seeds, or you can propagate them yourself to get new plants.
What are good companion plants for false sunflowers?
False sunflowers pair well with asters, yarrow, hyssop, reed grass, Russian sage, and if planted in containers, include some spiller plants such as million bells or lobelia.
How deep should you plant false sunflowers?
Plant false sunflowers that you get from the nursery or garden center to the same depth as they were in the previous container.