How to Grow and Care for False Sunflowers

The false sunflower, also commonly known as oxeye sunflower, is an easy-growing herbaceous perennial plant with double or single daisy-like, yellow-orange flowers surrounding a cone-shaped, golden-brown center disk. False sunflowers naturalize in grasslands and at the edge of woodlands but they thrive in a variety of settings, climates, soils, and light conditions, although full sun is best.

False Sunflower Care

Here are the basic tips on growing false sunflowers successfully.

• Give this plant as much full sun as possible.
• Grow in average, well-draining soil for best results.
• Keep the soil moderately moist.
• Don't fertilize often (or at all) to avoid leggy plants.
  

Light

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.

Soil

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.

Water

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 return yearly 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. 

Fertilizer 

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': a midsized plant with fluffy double flowers
• 'Loraine Sunshine': an early bloomer with variegated leaves
• 'Prairie Sunset': tall plant growing dark purple stems
• 'Summer Nights': dark red stems, red-tinged foliage, and gold flowers with mahogany centers
• 'Summer Sun': a tall plant with lots of semi-double golden flowers

Pruning

In the spring, pinch the tips off the ends of the stems to encourage branching out. Deadhead spent flowers to stimulate new buds. After the false sunflowers have stopped blooming in midfall, prune the plants to about 2 inches tall. You can also wait to prune them in the early spring after the threat of frost. 

Many varieties get top-heavy and require staking. Prune or pinch them back in midspring for a shorter, sturdier plant. However, doing this will delay blooming for a couple of weeks.

Propagating False Sunflowers

False sunflowers are clump-forming, staying in one place rather than spreading throughout the garden. Dividing your plants every two to three years will keep clumps from dying in the center. Do this in either the spring or fall with these steps.

1. Dig up the selected plant using a spade or shovel. Dig deep enough so you don't disturb the root ball.
2. Cut off any dead, mushy, or broken roots from the root ball with clean pruning shears before separating the plant.
3. Cut the plant in half or thirds using a clean, sharp knife.
4. Plant the divided plants immediately in a prepared suitable location and water the soil until it's 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.

To start seeds indoors, take these steps:

1. Plant seeds in rich, loamy, and well-draining potting soil.
2. Keep the growing medium somewhat moist but not overwet, and even opt for drier soil.
3. If started indoors, the seedlings can be planted outside once any danger of frost has passed.
4. Make sure to harden off seedlings before planting outside.

To direct sow seeds into the garden, do this:

1. Plant in moist but well-drained soil.
2. Plants should be spaced 18 to 24 inches apart.
3. Cover seeds with about 1/8 inch of dirt.
4. Water and plan to thin the seedlings as needed.

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. A clay pot will work best since the material is porous so it breaths better and keeps the soil from becoming soggy. Full sun and plenty of water will keep these adorning your patio or lanai, creating a colorful and beautiful arrangement.

Overwintering

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 into a garage area or placed in a protected location and elevated to avoid ground frost. 

Common Pests & Plant Diseases

In general, false sunflowers don't have any serious pest or disease issues. However, aphids and powdery mildew can be a problem for the plants. Provide good air circulation for your flowers to help prevent and mitigate these issues.

How to Get False Sunflowers to Bloom

Bloom Months

These bright, cheery flowers love to bloom and will start flowering in early July and go through August or early fall.

What Do False Sunflowers Look and Smell Like?

Scentless false sunflowers have yellow rays and an orange-yellow center disk. Although similar in looks, Heliopsis helianthoides is not the same as the perennial sunflower (Helianthus annuus) in the genus, and consequently, it's been given the common name of false sunflower.

How to Encourage More Blooms

Place false sunflowers in full sun and keep the soil moist and not dried out to encourage abundant blooms. Note that these plants grow fairly quickly but they likely won't bloom in their first year.

Deadheading False Sunflowers

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. 

Common Problems With False Sunflowers

False sunflowers are a native wildflower in a large portion of North America and they rarely cause any problems just about wherever they're grown. But as always, keep an eye out for a couple of minor issues.

Crumpled Leaves

If you notice crumpled or otherwise damaged foliage, check for an aphid infestation. Try removing aphids with a strong spray of water before turning to insecticides.

Leaves Have White Splotches

If you find splotches of white or gray on the leaves and stems of your false sunflowers, it's likely powdery mildew. Remove mildewed leaves, prune for good air circulation, and use fungicides if the problem persists.

Plants Look Leggy

If the plants start looking leggy or too tall, trim them back in the early summertime, which also helps produce new flowers.