Helenium is also known as sneezeweed and is an underutilized flowering perennial. It is referred to as sneezeweed because it blooms at the same time as ragweed, but it actually does not cause a person to sneeze nor is it an allergen. It grows 2 to 5 feet tall, starts blooming in mid-summer and will continue into the fall; just when most other perennials have started to lose steam. The blooms come in shades of yellow, orange and red and should be planted where it can get lots of sun.
Helenium grows best in garden zones 3 through 9 and the taller varieties require staking when they begin to bloom to prevent them from flopping over. Newer varieties grow less than 3 feet tall and generally don’t need such additional support. 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. Their preference for moist soil makes them a good candidate for use in rain gardens. They combine well in informal perennial or mixed beds and borders with Beebalm, Daylilies, fall-blooming Asters, Goldenrod, Solidago, Liatris, Coneflower, Black-Eyed Susans and other perennials. The shorter varieties work well with Sedge and other Ornamental Grasses and can be combined with the purple-flowering Verbena.
Many of the newer hybrids are more tolerant of drier soil. They require watering during dry periods and may benefit from fertilization in early spring when growth resumes. It is best to avoid overly rich soils or excessive fertilization which will promote lush foliage growth, but much fewer flowers. Pinching back new growth in late spring will produce shorter, sturdier plants, with a significant number of blossoms, but the flowering will be delayed. Taller types often end up with brown foliage before they bloom and leaf loss often results when plants dry out too much. They may need to be placed behind other plants to hide this unkempt foliage.
Clumps do not need frequent division, but spindly plants should be divided and replanted. Typically, the plant should be divided every 3 to 5 years or the plant may not grow as vigorously. The old central stalk should be removed. Separating and then planting clumps or individual plants will keep it vigorous and blooming well. Helenium has 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. It can also cause skin irritation to individuals with sensitive skin.
If you need a late-season, rear of the border plant for your garden then this is the plant for you.