Helenium — A great choice for the late summer garden
Helenium may be one of the most interesting wild flowers you’ve never heard of. Although widely distributed across North America, surprisingly, it is not as well known as it deserves to be. Curiously enough, this native North American perennial is commonly found in Europe where it was introduced in 1729. It eventually underwent extensive hybridization by British and German horticulturalists. In fact, Britain’s Royal Horticulture Society (RHS) is probably responsible for a resurgence of interest in this plant as a result of their perennial yellow daisy trials. Those trials were conducted between 1999 and 2001 and included 56 Helenium entries. Of those entries, 13 were awarded the RHS’s Award of Garden Merit at the end of the trial period. This award is essentially the Society’s “seal of approval” that the plant performs reliably in the garden. Coming full circle, some of those award winners eventually found their way back to American soil and are now more widely distributed through the nursery trade here.
Most sources state that Helenium was named in honor of Helen of Troy. Legend has it that the plant sprang from the ground wherever her tears fell. As Allan Armitage points out in his book “Herbaceous Perennial Plants,” this explanation sounds a little far fetched, considering the plant is of North American origin (whereas Helen of Troy was not). Nevertheless, the flower is sometimes referred to as Helen’s flower. But it is more commonly known as Sneezeweed because of its historical use as a form of snuff. American Indians used the dried leaves and flowers of this plant to induce sneezing as a way to relieve headaches and loosen up head colds. The snuff was also allegedly used to rid the body of evil spirits although there’s no proof that it worked.
DESCRIPTION OF THE HELENIUM GENUS
Helenium belongs to a genus of about 40 herbaceous perennials, annuals, and biennials that are found mostly in North, Central, and South America. It is an upright clumping perennial wildflower that grows 3 to 5 feet tall and 2 to 3 feet wide. Some of the compact cultivars top out at around 2 feet. An adaptable plant, it will grow in any site that has sun or part sun and wet to moist soils. Hardy in USDA zones 3 – 9, it grows in the wild along stream banks and in wet meadows or other wetland areas.
Bloom time varies by species but, in general, Helenium blooms from late summer into fall when most other perennials are done for the season. The dense clumps of narrow, toothed, lance-shaped foliage are crowned by an abundance of daisy-like flower heads in hues of golden yellow, burnt orange, and various shades of deep red. The flower petals are arranged in a single row of ray-like petals around a raised dome-shaped central disk. Each petal has distinct tooth-like indentations on the edges, which give rise to another common name, dog-tooth daisy. The three lobes on the edges help distinguish Helenium from Rudbeckia or other yellow coneflowers.
Helenium, like Solidago (goldenrod), has an undeserved reputation as a cause of hay fever and fall allergies. The flowers of this species are pollinated by insects rather than wind and have heavy, sticky pollen that cannot be easily inhaled. It blooms at the same time as ragweed, which is the true culprit.
Helenium attracts a variety of pollinators to the ornamental garden. It is particularly valuable in the late summer garden as a nectar plant for bees, butterflies, moths, and beetles.
The following describes a small sampling of the Helenium species found in the United States.
H. autumnale – Known as common sneezeweed, this species is native to eastern North America. It typically blooms for 8 weeks or more in late summer until frost. Of the nearly 40 species belonging to the Helenium genus, H. autumnale and its numerous hybrids have the greatest color and diversity. The native form of this plant produces bright yellow flowers, whereas its cultivars appear in various shades of yellow, orange, copper, and red.
H. bigelovii – This related species, commonly called Bigelow’s sneezeweed, is native to western North America and may be found in the wild in Oregon, California and Arizona. It bears 2” wide yellow flowers on plants that are 2’ to 3’ tall.
H. flexuosum – This eastern sneezeweed species, commonly called purple-headed sneezeweed, is native throughout the entire eastern and mid-western parts of the U.S. The 1.5” flowers on this 1’ to 3’ plant have drooping yellow petals. It is distinguished from other Helenium species by its prominent purplish-brown center disks.
H. hoopesii – This sneezeweed species is native to the western states of the U.S., where it is commonly referred to as Mountain Helenium, orange sneezeweed, or owl’s claws. This long-blooming 28” to 30” tall species produces large, 3” yellow flowers with orange centers. It grows from a taproot, so propagation from seeds is the best approach. Most Helenium hybrids contain some genes from H. hoopesii.
H. virginicum – Native to Virginia and Missouri, this rare wild flower is categorized as a threatened species under the Federal Government’s Endangered Species Act of 1973. In Virginia, it is categorized as an endangered species believed to exist in only two counties (Augusta and Rockingham) along the western edge of the Blue Ridge Mountains in the Shenandoah Valley. It bears bright yellow flowers on 2’ to 4’ tall stems.
With lively autumnal colors ranging from golden yellow to burnt orange, copper brown, or mahogany red and variations in between, this native herbaceous perennial is certain to be a welcome addition to the late summer ornamental garden. Of the cultivars listed In Allan Armitage’s “Herbaceous Perennial Plants” (Third Edition), ‘Crimson Beauty’, ‘Marti Gras’, and ‘Wyndley’ are perhaps best suited for smaller garden spaces, in his opinion. They are some of the shortest and sturdiest of the Helenium cultivars. The following are examples of the many Helenium cultivars available both in the U.S. and in Europe.
- ‘Butterpat’ – Yellow, an old favorite commonly found in garden centers, 4 – 5’ tall.
- ‘Coppelia’ – Coppery orange, reputed to have sturdy stems, 3’ tall.
- ‘Crimson Beauty’ – Mahogany brown, 2 – 3’ tall.
- ‘Dark Beauty’ – Bright red, white ray bases, 6’ tall.
- ‘Kugelsonne’ – Butter yellow, 3 – 4’ tall.
- ‘Marti Gras’ — Yellow flowers aging to orange, rich chocolate brown centers, 3 – 4’ tall.
- ‘Moerheim Beauty’ – Mahogony red, one of the best of the older varieties with large, eye-catching multicolored flowers, 3 – 4’ tall.
- ‘Pumilum Magnificum’ – Soft yellow, 4 – 5’ tall.
- ‘Red and Gold’ – Red and gold, 3 – 4’ tall.
- ‘Riverton Beauty’ – Golden yellow, 3 – 4’ tall.
- ‘Ruby Tuesday’ – Burgundy flowers with mahogany centers. A profuse blooming and compact variety, reaching 20” to 30” tall.
- ‘The Bishop’ – Large, deep yellow flowers and dark centers, blooms earlier than other varieties, 3’ tall.
- ‘Wyndley’ – Coppery brown, 2 – 3’ tall.
- ‘Zimbelstern’ – Yellow rays, red and yellow bicolor center, 3 – 4’ tall.
CULTURAL REQUIREMENTS AND MAINTENANCE OF HELENIUM SPECIES
Helenium thrives very nicely in blazing hot sun. However, it has wide-spreading, shallow roots that are happiest in moisture-retentive soil that has been amended with compost or other organic matter. Moist soil or even poorly drained soil is fine with this plant because the moisture helps keep its roots cool. An established plant can tolerate drier growing conditions, but flower size may be smaller. Therefore, it’s generally best to provide supplemental watering during hot, dry weather. A layer of mulch is also beneficial for keeping the roots cool and retaining moisture in the soil.
If you don’t have a sunny site, no problem. Helenium can take partial shade but the colors may not be as good. Reds, in particular, may not be as saturated.
While compost is recommended for this plant, fertilizer is not. It is a fast-growing species and fertilizers can cause tall, weak stems that flop.
When the plants reach 6 to 8 inches in spring or early summer, pinch them back to encourage strong branching and denser growth. They may also be pinched back later in the growing season but bloom time may be delayed.
If you do not cut back the taller selections to make them shorter and sturdier, they may need to be staked to keep them from flopping over. This is particularly true if they are being grown in an exposed or windy site. If you know the variety you’re growing is prone to weak stems, it’s wise to stake the plant before it becomes very tall. Hot weather can promote tall, weak growth.
Once the plant begins to bloom, deadhead spent blossoms regularly to prolong flowering. If snipping off each blossom individually seems like too much effort, you can shear about 4 to 6 inches off the top of the plant instead. Deadheading the cultivars will also remove the possibility of dissimilar plants sprouting up within the clump.
Cut the plant back to the ground in fall after flowering is complete.
In time, Helenium clumps will become denser with decreased flowering. To maintain plant vigor, dig up the plant in spring or fall and divide it. The clumps are easy to divide and benefit from division about every 3 to 4 years.
Helenium may also be propagated by seed. If starting seeds indoors, sow them in spring about 8 to 10 weeks before planting them outdoors. Just barely cover them with soil and keep them moist until they sprout. Note: Seeds from cultivars will not come true to the “parent.” If that’s a concern, then stick with either divisions or buy fresh plants. On the other hand, if you like to experiment, the seeds from cultivars may prove to be very interesting.
PESTS AND DISEASES OF HELENIUM
Although generally pest resistant, slugs and snails may damage the emerging plant foliage in spring. This is generally a short-term problem and unlikely to affect the plant over the long haul.
Mildew may affect the plant, in which case, the best approach is to cut the plant back by half or two-thirds after it finishes blooming. This will help prevent further mildew outbreaks.
For the gardener plagued with deer or rabbit problems, this plant is unpalatable to herbivores. Do note that this plant, including its flowers, foliage, and seeds, are poisonous if ingested and can potentially cause vomiting or convulsions.
USES OF HELENIUM IN THE LANDSCAPE
Helenium is good for naturalizing and generally looks best planted as a grouping or as a mass planting. It pairs well with other perennials and grasses including asters, Boltonia, Joe Pye Weed (Eupatorium), Liatris, Monarda, late blooming salvias, goldenrod (Solidago), tall sedum, switch grass (Panicum virgatum) or big bluestem (Andropogon). As a general rule, it looks best planted with other “hot” colors but it also looks good planted near blue or purple-flowering plants. Try it in:
- Informal prairie or meadow settings. Combined with Echinacea, asters, and other daisy-like flowers that like similar growing conditions, it will attract a broad range of beneficial insects to the garden.
- Cottage gardens, where the taller varieties look best in the middle or back part of the border.
- Butterfly gardens as a source of late summer nectar for bees and butterflies.
- Water-wise landscapes, swales, bioretention basins, and rain gardens.
- Moist soils bordering ponds or other bodies of water.
- Sunny mixed-perennial borders.
- Flower arrangements. It holds up well as a cut flower.
Although Helenium is native throughout all of North America, it is not all that widely known to most gardeners. That may change depending on the outcome of two prestigious plant evaluation programs that are currently underway. Just this year, the Chicago Botanic Garden’s Plant Evaluation Program embarked on a 4-year comparative field trial of 39 Helenium species and cultivars. A report of their findings and recommendations of top performers to gardeners and the horticulture industry will presumably become available at the end of the study in 2021. Coincidentally, the Mt. Cuba Center in Delaware also began a Helenium field trial this year. According to their website, their 3-year trial of 43 selections will focus on the horticultural characteristics of “sturdiness, bloom time, bloom quantity, and resistance to diseases like powdery mildew and rust.” In addition, the study will assess the ecological value of this plant to pollinators. The results of their trial will be released in 2019. If you don’t want to wait for the results of these plant trials, try growing one or two Helenium species or cultivars now. You won’t be disappointed.
Herbaceous Perennial Plants, A Treatise on their Identification, Culture, and Garden Attributes, Third Edition (Armitage, Allan M., 2008)
Perennial Combinations (Burrell, C. Colston, 2008)
The Well-Tended Perennial Garden (DiSabato-Aust, Tracy, 2006)
Chicago Botanic Garden Plant Evaluation Program (chicagobotanic.org/research)
Mt. Cuba Center Field Trials on Helenium (mtcubacenter.org/trials/helenium)
Piedmont Virginia Native Plant Database (www.albemarle.org/NativePlants)
“Virginia Sneezeweed (Helenium virginicum), U.S. Fish and Wildlife Service’s Environmental Conservation Online System Species Profile (ecos.fws.gov)
“Virginia Sneezeweed,” Virginia Natural Heritage Resources Fact Sheet (dcr.virginia.gov)