Heliopsis Helianthoides ‘Tuscan Sun’

June 15, 2010 - 09:11

Every so often, a breeder introduces a new perennial cultivar that vastly improves on preexisting cultivars. Heliopsis 'Tuscan Sun' is a fairly recent Proven Winners introduction that offers such enhancements and provides the 'Wow!' effect, both in containers and garden settings. 'Tuscan Sun' is compact, produces an abundance of flowers, and is fairly resistant to powdery mildew.

'Tuscan Sun' forms attractive clumps reaching 15-18 inches tall when in bloom by 20-24 inches wide at maturity. It produces numerous daisy-like flowers with yellow petals that shoot out from the golden, circular centers all summer long above attractive foliage on strong, sturdy stems. Heliopsis grows best well in sunny locations throughout USDA Hardiness Zones 3 to 9. Once established in the landscape, this tough plant can tolerate a great deal of abuse, including heat and drought stress; however, plants produced in containers will require more frequent irrigation.

With its ease of production and show-stopping appearance, 'Tuscan Sun' has received numerous awards in recent years, including 2009 Knock Your Socks Off from the University of Georgia, 2009 Best Performer from Michigan State University and 2009 Top Performer from University of Kentucky Arboretum.

'Tuscan Sun' is a fierce, sunny variety that will be sure to attract the attention of passersby. It is great as a mass planting, as an accent in beds and borders, or in containers.

Propagation
Heliopsis 'Tuscan Sun' is vegetatively propagated by tip cuttings by a limited number of licensed propagators; self-propagation is strictly prohibited. Rooted liners are available in various sizes. See page 51 for a listing of the current licensed propagators.

Production
'Tuscan Sun' is well suited for production in small (5-inch) to intermediate-sized (one-gallon) containers. It performs best when it is grown in a good quality, well-drained peat or bark based growing medium. Plant one plug liner in the center of each container such that the original soil line of the liner is even with the surface of the growing mix of the new container. Although it branches freely, a pinch two weeks after trans-planting promotes fullness and increases the number of blooms; large container sizes may require two pinches.

Heliopsis requires moderate to moist irrigation; it will require more water as the crop progresses and approaches flowering. Water as needed when the plants are young and becoming established. Once they are well established, more frequent irrigations will be necessary. Keep them moist but not saturated during production.

They require a moderate amount of fertility. Nutrients can be delivered using water-soluble or controlled-release fertilizers. Growers using water-soluble fertilizers apply 100- to 150-ppm nitrogen with every irrigation or use 250-300 ppm as needed. Controlled-release fertilizers are commonly applied as a top-dress onto the media surface using the medium-recommended rate on the fertilizer label, or incorporated into the growing medium prior to planting at a rate equivalent to 1.0-1.25 pounds of elemental nitrogen per yard of growing medium. The pH of the media should be between 5.8 and 6.4.

Given this plant's compact habit, plant growth regulators usually are not necessary. But the plants can be toned with a foliar application of daminozide (B-Nine or Dazide) at 2,500 ppm.

Insects and Diseases
Although heliopsis can be produced relatively insect free, aphids, leafminers, thrips and whiteflies often can be observed feeding on them. The most common diseases of false sunflower are leaf spots (Ascochyta, Cercospora, Phyllosticta and Septoria), rust and powdery mildew, which is the most prevalent. To reduce the occurrence of powdery mildew, provide proper plant spacing and adequate air movement, and control the humidity. Or, if desired, follow a preventive spray program using the appropriate chemicals.

Insects and diseases can be detected with routine crop monitoring; control strategies may not be necessary unless the scouting activities indicate actions should be taken.

Forcing
Blooming plants of 'Tuscan Sun' can easily be grown for late spring and summer sales. Heliopsis does not require vernalization to bloom. Plants will easily bloom from unvernalized starting materials. They are obligate long day plants, absolutely requiring long days to flower. In fact, they require long photoperiods both to grow and flower. Under short natural days, long day lighting must be provided to keep heliopsis actively growing and promote flower development. Long days can be provided using day extension (14- to 16-hour days) or night-interruption lighting.

The amount of time it takes to produce flowering plants after the proper photoperiod is provided is a function of temperature. Heliopsis 'Tuscan Sun', grown at 68° F, will take approximately eight weeks to reach flowering; plants grown at 60° F will flower in about 10 weeks. If the plants have been pinched to promote branching, add approximately three weeks to the production time for each pinch.

Availability
Heliopsis 'Tuscan Sun' was brought to the market by Plant Haven, Inc. (www.planthaven.com) and is currently being marketed by Proven Winners (www.provenwinners.com). Rooted liners are available from several licensed propagators: EuroAmerican Propagators (www.pweuro.com), Four Star Greenhouses (www.pwfourstar.com), Pleasant View Gardens (www.pwpvg.com) and Skagit Gardens (www.skagitgardens.com).

About The Author

Paul Pilon is a horticultural consultant, owner of Perennial Solutions Consulting (www.perennial-solutions.com) and author of Perennial Solutions: A Grower’s Guide to Perennial Production. He can be reached at paul@perennial-solutions.com or 616.366.8588.

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