10/28/2015
Growing Hardy Sunstruck Heliopsis
Karl Batschke
With its strikingly variegated foliage and season-long flowering,
Heliopsis helian-thoides Sunstruck is a stunning addition to the perennials garden or mixed containers. These heat and sun lovers are native to North America and typically hardy to Zone 4 or even colder under ideal conditions. They’re relatively easy to grow with a little understanding of their cultural requirements.
Propagation
Our trials suggest that Sunstruck Heliopsis root best when given low to moderate mist regimes. We’ve seen excellent rooting results when the basal end of cuttings is dipped in IBA rooting hormone concentrations of 500 to 1,000 ppm. We’ve trialed water-
soluble IBA sprays of 300 ppm with limited results and higher rates have caused leaf burning. Also, we’ve received reports that Capsil and Heritage have caused defoliation in propagation. Best to avoid these products on Sunstruck Heliopsis.
Rooting temperatures of 70 to 74F
(21 to 23C) are ideal. Cooler temperatures delay rooting and contribute to lower rooting yields. Sunstruck Heliopsis is an obligate long-day plant. Long days must be provided in propagation. This can be accomplished with many forms of lighting, including HID, LED, CFL or incandescent lights. Extended day lighting to provide 14 hours of total daylength (rather than night interruption) is the preferred method.
Growing on
When growing Sunstruck Heliopsis, transplant into a well-drained media, such as a traditional perennial composted bark mix with pH adjusted to 5.8 to 6.4 and EC of 0.8 mms. Heliopsis are moderate feeders and respond well to liquid feeds of 125 to 150 ppm on a constant basis or incorporated slow-release fertilizers of 1.0 to 1.25 lbs. of nitrogen per cubic yard. Excessive fertilization will result in fewer flowers and less variegation in the foliage.
Sunstruck Heliopsis can be grown using a traditional summer planting schedule or it can be spring planted since no vernalization is required for flowering. When summer planted, be sure that plants are well established in the final containers prior to the start of natural short days. Heliopsis will go into complete dormancy as the days approach 10 hours in length. They’re reliable plants in over-wintering programs and will begin to emerge naturally as daylength exceeds 11 hours and as average temperatures exceed 50F (10C).
Spring planted programs will require plants be grown under long days until April 1. At this time, days are long enough to keep Sunstruck Heliopsis actively growing. This can be more easily achieved by growing plants in a large-cell liner under extended day conditions, as described above, and then shifted to final containers April 1 or later.
When spring planting, it will be necessary to perform multiple pinches to achieve uniform, full plants. We recommend two pinches in the young plant stage and one general shearing of the finished product 4 to 6 weeks prior to sending to retail. Sunstruck Heliopsis can be sheared back at any time under long days and plants recover and rebloom quickly—typically in less than 4 weeks.
Because Sunstruck Heliopsis was bred and selected to be naturally short and well branched, PGRs are generally not necessary. If growing conditions are contributing to plant stretch, a foliar spray of 2,500 ppm of B-Nine and 800 ppm of Cycocel will help tone and reduce stretch.
Pests & diseases
Sunstruck Heliopsis are relatively free from common diseases, such as powdery mildew and rust, as well as leaf-spot diseases. Watch for spider mites and thrips and treat accordingly.
Sunstruck Heliopsis was bred and developed by Darwin Perennials and is available from Darwin Colombia, Dümmen Florexpo or from any Darwin Perennials licensed rooting station.
GT
Karl Batschke is Global Product Manager for Darwin Perennials. Visit www.darwinperennials.com.