CULTURE NOTES
4/27/2011

Cultivating Sombrero Echinacea

Karl Batschke
In 2010, the industry saw PanAmerican Seed’s PowWow Wild Berry Echinacea earn an All-America Selections award because of its proven grower and garden performance. New for the echinacea category in 2012 is the Sombrero series from Darwin Perennials. Its genetics are selections straight out of the fields from the PowWow breeding program.

Most notable in the Sombrero series is that selections were made from overwintered plants that are hardy to at least Zone 5. This is contrary to other brightly colored echinacea classes on the market, which may reach Zone 6.

The brightly colored Sombreros are single-flowered echinacea that feature the same well-branched and compact habit as the floriferous PowWows. With hues such as Hot Coral, Salsa Red and Sandy Yellow, they’ll be appealing to home gardeners at retail. For growers, they can be produced as first-year flowering or overwintered perennials, and are well matched for timing and habit.

Sombrero genetics make them extremely well-branched, and they’ll fill a gallon container nicely in a spring planting and subsequent June/July flowering for retail. From a supply standpoint, the Sombrero series is dependable, and will be offered as tissue culture liners.

Production as a first-year flowering perennial

With Sombrero’s vigor and basal branching, a single plug will easily fill quart- or gallon-sized containers. Plant Sombrero varieties prior to week 10 to let them develop under short days.

Transplant liners into a well-drained soilless medium and provide two to three weeks of rooting-out temperatures of 68F to 72F (20C to 22C), then grow at a day temperature of 60F to 65F (16C to 18C) and night temperature of 55F to 60F (13C to 16C). Plant growth stalls below an average daily temperature of 55F (13C). Like other echinacea cultivars, these thrive in a high light intensity. Sombreros are moderate feeders requiring weekly fertilization at 175 to 200 ppm using nitrate-form fertilizer with low phosphorus and high potassium. Maintain a medium pH of 5.8 to 6.2. The plants will flower in 14 to 16 weeks, depending on the temperature and light conditions. Their best flowering occurs with a 14-hour photoperiod.

One of the standout features of Sombrero is that it’s naturally compact and well-branched; therefore plant growth regulator (PGR) applications are not required. However, if needed under your production conditions, apply PGRs four weeks after transplant based on your trials. All common commercial PGRs effectively suppress Sombrero’s height.

Production as an overwintered perennial
Sombrero will overwinter at temperatures just above freezing. Prior to overwintering, plants should be fully rooted and drenched with a broad-spectrum fungicide. Maintain plants on the dry side, as wet pots are susceptible to root rot and possible plant losses. Plants will regrow once temperatures are above 55F (13C). As plants resume rapid growth, water and fertilizer levels should be gradually increased. In our trials, overwintered Sombrero looks even more amazing with even greater branching than those grown as first-year flowering perennials. GT


Karl Batschke is the global products manager for Darwin Perennials. He can be reached at kbatschke@ballhort.com, or visit www.darwinperennials.com.
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