How to Grow and Care for Helenium (Sneezeweed)

Helenium (Helenium autumnale)—commonly known as sneezeweed—is native to the United States and southern Canada. Helenium grows in moist, low-lying meadows or at the edges of damp woodlands. Horticulturists have taken the genus far beyond the simple yellow daisy-like flower of the native type, though, expanding the varieties to include every conceivable shade of gold, orange, red, and brown. The blooms of helenium attract butterflies in late summer and fall.

The plants are characterized by lance-shaped foliage with stiff, upright stems. Some taller cultivars need staking. Helenium is planted in early spring. Its simple charm suits cottage gardens and wildflower gardens. Pair helenium plants with other moisture-loving ornamentals that peak late in the season like beautyberry or hibiscus. For the best effect, plant helenium in groups of three or five.

Helenium Care

Here are the main care requirements for growing helenium: 

• Plant helenium in a location with full sun and well-drained, moist, acidic soil.
• Space plants 3 to 4 feet apart to ensure good airflow.
• Keep the soil moist and water as needed.
• Pinch plants in the spring to encourage branching.
• Deadhead spent flowers to encourage continuous bloom.
  

Light

Helenium flowers will get leggy if they don’t receive at least six hours of sun each day, but they will accept some afternoon shade, especially if the planting area tends to be dry.

Soil

Helenium plants like their soil on the acidic side, with an ideal pH range of 5.5 to 7.0. Place heleniums where they will enjoy moist conditions, but not in a boggy site. Consider a rain garden site where moisture naturally collects, such as a low-lying area or beneath a downspout. Well-draining soil is best, but heleniums are clay tolerant.

Water

The plants need moderate to heavy moisture; they are not drought-tolerant so they need to be watered in the absence of rain. A 3-inch layer of organic mulch will conserve moisture.

Temperature and Humidity

Helenium plants tolerate humidity and hot summers, but proper spacing is important to prevent fungal diseases like mildew and rust where humidity is high.

Fertilizer

Heleniums aren’t heavy feeders, and one application of a balanced flower fertilizer in the spring, following product label instructions, is enough in fertile soils. Excessive fertilizer causes lanky growth.

Types of Helenium

For such a seemingly simple and underused perennial, the number of helenium cultivars is surprising. Variations in flower form, height, and color allow gardeners to devote an entire plot to growing helenium if they wish. Here are a few of the most interesting selections for your garden:

• 'Adios': Purplish-brown prominent cones; downturned petals
• 'Beatrice': Yellow petals more upward than most varieties; yellow and brown cone
• 'Butterpat': Pure yellow flowers from petals to cone
• 'El Dorado': A large brown cone flanked by a petticoat of lemon-yellow petals
• 'Red-Haired Katy': Petal color seems to shift from crimson to copper depending on the light
• 'Waldtraut': Long blooming time; orange petals flecked with gold

Pruning

Pinching helenium in the spring encourages shorter, stronger, sturdy plants and branching. Deadhead spent flowers to encourage subsequent blooming. After blooming, cut the flower stalks down to the foliage.

Propagating Helenium

Helenium is easily grown from seed but can also be propagated through cuttings. Here's how: 

1. In the spring, using scissors or pruners, take a 4- to 6-inch cutting of a soft, green stem just below a node. 
2. Remove the bottom leaves.
3. Dip the cut end in water then in rooting hormone.
4. Slide the cutting about 2 inches into 4-inch pot filled with damp potting mix.
5. Keep warm and moist but not soggy in a warm location out of direct sunlight.
6. Once you see new growth, the cutting has rooted. Wait until it has become a vigorous little plant before transplanting it into the garden.

How to Grow Helenium from Seed

You can choose seed starting to get a large colony of helenium growing quickly.

1. Sprinkle the seeds liberally on moist ground in fall so they can break dormancy naturally.
2. Don't cover the seeds because they require light to trigger germination.
3. Seeds will germinate in the spring about two weeks after soil has warmed.

Potting and Repotting

Helenium is ideally planted in the landscape but it can also be grown in containers. Select a container with large drainage holes and fill it with well-draining potting mix. Keep in mind that container plants need more frequent watering and fertilization than plants in garden soil.

Also, although helenium is winter-hardy even in areas with harsh winters, growing the plant in a container exposes its roots to the cold, which can lead to plant death. Leave the plant outdoors all winter but winterize the container by sinking it into the soil or placing it inside a planting silo.

Overwintering

Helenium is a hardy perennial but to help it get through the winter, it helps to spread a 6-inch layer of hay or mulch over your helenium bed. In the spring, as soon as the frost danger has passed, remove the insulating layer.

Common Pests & Plant Diseases

Helenium plants are renowned for their hardiness and disease resistance, but if they are crowded—especially in shaded areas—they can suffer from powdery mildew or leaf spot.

How to Get Helenium to Bloom

Bloom Months

Helenium typically blooms between July and September. 

How Long Does Helenium Bloom?

Under ideal conditions, it blooms for 1 to 2 months from the summer into the fall.

What do Helenium Flowers Look and Smell Like?

The daisy-like flowers resemble coneflowers, blanket flowers, and black-eyed Susan flowers. They are 2 inches in diameter, with wedge-shaped bright yellow rays and dome-like, protruding center disks that are dull in color. The flowers have no particular fragrance. 

How to Encourage More Blooms

The reason for poor bloom is usually too much shade. To get them blooming, move them to a sunnier spot. If the plants are growing well but there is mostly foliage and no or few flowers, you might have fertilized them too much. Stop fertilizing them to see if that encourages more flowers. Deadheading the spend flowers encourages more blooms. Decreased flowering after three to four years can also be a sign that the plant needs to be rejuvenated by division. 

Caring for Helenium After It Blooms

Other than cutting the flower stalks back to the foliage after the bloom, there is no other care needed.

Deadheading Helenium Flowers

Although helenium naturally blooms for a long time, deadheading the flowers helps to ensure a continued bloom.