The genus Helenium in the daisy family (Asteraceae) includes more than 40 species of annuals and perennials from the Americas. The types most commonly used as garden plants are hybrids created with H. autumnale as a primary parent. With common names of Helen’s flower, sneezeweed (somewhat misleading since they do not cause allergies but got that name from the historic use of crushed dried leaves and flowerheads in snuff intended to cause sneezing that was supposed to drive evil spirits from the body) or just plain helenium, H. autumnale is a highly variable perennial native to much of the US and southern Canada hardy in USDA zones 3–8. The wild forms with primarily yellow flowers are likely to appeal mainly to native-plant enthusiasts, while the more refined hybrids are well suited to most ornamental gardens. As with many American wildflowers and grasses, Europeans, especially in Germany and the Netherlands, have been instrumental in developing helenium into more vigorous plants with better form, a longer bloom period and a wider palette of more vivid colors in autumn shades of gold, orange, red, and brown. Many modern hybrids include some orange sneezeweed (H. hoopesii, a western species that blooms in midsummer), so that many start blooming earlier than older types and continue until fall.
These erect, clump-forming herbaceous perennials grow 2-5 feet tall from a crown of resting shoots with shallow, fibrous roots. The alternate, medium green lanceolate to elliptic-oblong leaves to 6 inches long have sparsely toothed to almost entire margins. The base of the leaves often clasp the stems. The rigid, angular, winged, slightly hairy stems branch near the top.
Heleniums generally produce abundant velvet-textured flowers in dense terminal clusters over a long period of time. The exact time varies by cultivar, with some blooming as early as June, but most flowering in late summer to autumn (sometimes to first frost). The 1-2 inch wide flowers have the typical composite or daisy pattern, with ray florets surrounding the central disk flowers. In most heleniums, the 11-21 ray flowers are relatively short and wedge-shaped with notched ends forming three lobes at the tip. They may be held in a flat plane or droop downwards. The prominent center is subglobose – forming a dome-like, round knob – so the overall effect of the flower heads is sculptural and elegant. The ray flowers range in color from pale or bright yellow to gold, warm orange, coppery brown and deep red, and sometimes with two or more colors blended together for a washed or stippled effect, or striped or with bands of color. Consistent deadheading promotes more flowers; large groups of plants can be sheared. The flowers are frequently visited by butterflies, bees and other insects and are excellent for cutting. The tiny disk florets are eventually replaced by seeds (achenes that lack tufts of hair) that are often dispersed by water.
These late-season bloomers can be used in beds, cottage gardens, prairies, meadows, wild gardens, and naturalized areas especially when planted in drifts or masses. Because they like moist soil they can be used in rain gardens. They combine well in informal perennial or mixed beds and borders with ornamental grasses, anise hyssop (Agastache foeniculum), beebalm (Monarda spp.), daylilies, fall-blooming asters, goldenrods (Solidago spp.), leadwort (Ceratostigma plumbaginoides), liatris, purple coneflower (Echinacea purpurea), rudbeckias, and many other perennials. Shorter cultivars would work well with bronze carex (most are not hardy in our area, however) and mix nicely with the airy purple-flowerd Verbena bonariensis (not hardy, but self-seeds readily).
Helenium does best in full sun in rich, moist soil, although many of the hybrids are more tolerant of relatively drier soil. Plants require watering during dry periods and may benefit from fertilization in early spring when growth resumes. Avoid overly rich soils or excessive fertilization which will promote rampant foliar growth and fewer flowers. Taller types may need to be staked to prevent flopping when they begin to bloom (or use pea staking, or tie plants grown in drifts together with string). Pinching back new growth in late spring will produce shorter, sturdier plants, with more floriferous bloom but flowering will be delayed. Taller types often end up with ragged foliage before they bloom (leaf loss often results when plants dry out too much), so may need to be disguised behind other plants. Cut back the stems after flowering or in early spring before growth resumes.
Clumps do not need frequent division but spindly plants should be divided and replanted. These plants have few pest problems but powdery mildew and leaf spots can affect the foliage. They are not favored by deer or rabbits because the bitter foliage is toxic if ingested in large quantities, and can cause skin irritation in susceptible people.
The species are easily grown from seed but hybrid heleniums are propagated from divisions or tip cuttings made in early spring just as they start into growth. Dig clumps every 3-5 years, discarding the old central stalk and separating groups or individual rosettes, to keep the plants vigorous and blooming well.
Just a few of the numerous cultivars and hybrids available offering a range of flower form, height, and color include:
- ‘The Bishop’ – is a compact selection (28 inches tall) of the west coast species H. bigelovii with deep yellow ray flowers surrounding a black-brown center. It is listed as much less hardy than other heleniums, blooming in the middle of the season.
- ‘Bruno’ – is a midseason bloomer with dark mahogany red-brown flowers on 3 to 3½ foot tall plants.
- ‘Butterpat’ – has bright yellow ray flowers and a prominent yellow-green disk on plants 4 feet tall or taller. It received the Royal Horticulture Society’s Award of Garden Merit in 2001.
‘Double Trouble’ (PP18206) – has double, sterile flowers that are produced over a long period from midsummer through early fall. The pure bright yellow frilly ray flowers surround a gold disk.
- ‘El Dorado’ – is an early and long-flowering cultivar released in 2005 featuring mostly yellow flowers with slight streaks of red down the petals on 3 foot tall plants.
- ‘Feuersiegel’ (“fiery lightning bolt”) – is one of German nurseryman Karl Foerster’s very free-flowering releases (1959) with deep yellow flowers marked with forked streaks of red radiating from the light brown disk (the amount of red varies with temperature and light levels, so may appear as red edged with yellow) on 4 foot tall plants. This late-blooming cultivar received the Royal Horticulture Society’s Award of Garden Merit in 2001.
- ‘Goldrausch’ (“gold rush”) – another Foerster cultivar with golden yellow flowers marked with brown and a green-brown disk on tall plants (4-5 feet).
- ‘Hot Lava’ – is a newer, very floriferous variety from the Netherlands with long-lasting orangey red flowers with upturned petals around disks that begin yellow and change to maroon when mature on 2½ foot tall plants. (Very similar to “Ruby Charm”)
‘Mardi Gras’ – is a patented variety with numerous flowers with ray petals in shades of rich orange washed with yellow and red on 2-3 foot tall stiff-stemmed plants. Plants can begin blooming as early as late June into October. Zones 4-8.
- Mariachi™ Salsa – is a compact and floriferous variety with reddish-orange ray flowers around a brown cone from midsummer through fall on 20 inch tall plants. Mariachi™ Siesta has red-purple ray flowers.
- ‘Moerheim Beauty’ – is one of the most well-known and popular varieties, developed by Dutch breeder Bonne Ruys in the 1930s. This early bloomer has reddish bronze flowers in a range of shades, with some flecked with gold or copper, maturing to russet, around a dark center on 3½-4 foot tall plants which often need support.
If deadheaded thoroughly it will reflower later in the season. It received the Royal Horticulture Society’s Award of Garden Merit in 2001.
- ‘Potter’s Wheel’ – is a late season flowering Dutch hybrid with deep cherry red flowers with a narrow gold edge surrounding a maroon center on 4 foot tall plants.
- ‘Pumilum Magnificum’ – is an English variety that has been grown in gardens since the late 1890’s with early deep, pure yellow flowers on 2 foot tall plants (“pumilum” means dwarf).
- ‘Ring of Fire’ – is a semi-double Dutch introduction with two layers of orange and yellow petals.
- ‘Rubinzwerg’ (“ruby dwarf”) – is a poplar cultivar released by Peter and Bärbel Zur Linden in 1989 with red petals that have a hint of yellow near the cone, flowering from mid-summer to fall. The bushy plants are a little over 2 feet tall. It received the Royal Horticulture Society’s Award of Garden Merit in 2001.
- ‘Sahin’s Early Flowerer’ – is a long-flowering hybrid introduced by an Englishman, named after the Dutchman in whose nursery it was discovered, that starts blooming in mid-summer and continues until frost. Flower color changes from reddish-orange in hot weather to yellow in cool weather and each orange flower is different from the next. It received the Royal Horticulture Society’s Award of Garden Merit in 2001.
‘Short ‘n’ Sassy’ – is a compact cultivar that grows only 20 inches tall and wide, with golden-orange ray flowers around the dark cone in summer and fall. Zones 4-8.
- ‘Waltraut’ (a girl’s name, the female form of Walther) – is an older German variety (introduced by Gustav Deutschmann in 1947) with orange petals flecked with gold that deepen in intensity of orange as they mature. It begins blooming from early July on 2½ foot tall plants and received the Royal Horticulture Society’s Award of Garden Merit in 2001.
– Susan Mahr, University of Wisconsin – Madison