November 2010 Culture

Perennial Solutions: Geum ‘Totally Tangerine’ By Paul Pilon

Those who like the bright, cheerful displays of color that many geum cultivars deliver in the early spring, but wish these plants would bloom into the summer months, I'd like to introduce you to Geum x hybrid 'Totally Tangerine' (aka 'Tim's Tangerine' PPAF). Thanks to the breeding efforts of Tim Crowther from the United Kingdom, there is now an impressive, long blooming geum cultivar on the market.

'Totally Tangerine' develops attractive mounds of deep-green, fuzzy pinnately lobed leaves. In the landscape, an individual plant will grow to 18 inches across and reach 24-30 inches when in flower. It blooms slightly later than many of the geum cultivars on the market; blooming begins in the late spring, but unlike most cultivars, flowering continues through the heat of summer. With the flowers being sterile, it continues to bloom and bloom, producing hundreds of warm, bright-apricot to tangerine-orange single flowers over the course of the growing season.

Geum performs well across much of USDA Hardiness Zones 4 to 9 and AHS Heat Zones 9 to 3 where they prefer to be grown under partial shade; however they can tolerate several hours of direct sunlight each day. Once established in the landscape, geum has shown good tolerance to drought. 'Totally Tangerine' makes a great addition to herbaceous perennial borders, are well suited for commercial landscape plantings, and makes a great cut flower. Avens attract butterflies into the gardens and are resistant to deer and rabbit feeding.

Propagation

Geum 'Totally Tangerine' is vegetatively propagated from softwood or root cuttings. A U.S. Plant Patent has been applied for (PPAF); propagation without permission of the applicant is illegal at this time.

Production

Growers commonly transplant one rooted liner into 1-gallon or larger sized containers. 'Totally Tangerine' can be started in either the fall prior to or in the spring of the same year they are intended to be sold. When transplanting, the plugs should be planted so the original soil line of the liner is even with the surface of the growing medium of the new container. Geum performs best when they are grown in a moist, well-drained medium with a slightly acidic pH: 5.8-6.4. They require an average amount of irrigation and do not tolerate extended periods of saturated or overly dry growing conditions. It is best to keep them uniformly moist, but not consistently wet.

Geum can be grown using low to moderate fertility levels. Growers using water-soluble fertilizers either apply 150-200 ppm of nitrogen as needed or feed with a constant liquid fertilization program using rates of 75-100 ppm of nitrogen with every irrigation. Controlled-release fertilizers can be applied as a top-dress onto the media surface using the medium labeled rate, or incorporated into the growing mix prior to planting at a rate equivalent to 0.9 to 1.1 pounds of elemental nitrogen per yard of growing medium.

It is not usually necessary to control plant height in the early stages of production. However, as the plants approach flowering it is often beneficial to implement some height management strategies to reduce plant size. The first strategies entail providing adequate space between the plants and avoiding excessive nutrient and/or moisture levels during production. If additional height control is needed, several commercially available plant growth regulators effectively control elongation. Applying multiple spray applications of paclobutrazol (Bonzi, Paczol or Piccolo) at 30 ppm or uniconazole (Concise or Sumagic) at 5 ppm every seven to 10 intervals (two to three applications) should provide adequate height control.

Insects and Diseases

Occasionally, aphids, black vine weevil, leafminers and spider mites may be observed feeding on geum causing only a minimal amount of injury. Of these insect pests, aphids occur the most frequently. The primary diseases growers should watch for are Botrytis, downy mildew, powdery mildew, root rots and rust diseases. None of these pests require preventative control strategies. Growers can detect the presence of insects and diseases using routine scouting programs and determine if and when control strategies are necessary.

Forcing

Geum 'Totally Tangerine' is typically produced for mid-spring sales. Although flowering does occur without vernalization, it is cold beneficial and will flower earlier and more profusely following a cold treatment. Like other geum cultivars, 'Totally Tangerine' is classified as a day-neutral plant and will flower under any photoperiod.

To obtain the earliest bloom time, it is best to plant liners into the final container during the early fall, allow them to become established and bulk up slightly, vernalize them, and then force them to bloom in the early spring using moderate to low production temperatures, 60-65¼ F. Plants that have been vernalized will flower in six to eight weeks at these temperatures. To produce blooming plants for mid season sales, vernalized liners can be transplanted in the late winter and if late season sales of this variety are needed, then unvernalized or fresh liners can be used. When planting in the spring using unvernalized 72-cell liners, it typically takes six to eight weeks to grow quarts and 10 to 12 weeks to produce 1-gallon sized containers.

Availability

Geum x hybrida 'Totally Tangerine' is brought to the market by Plant Haven, Inc. (www.planthaven.com). Rooted liners are available from several licensed propagators including Gulley Greenhouse (www.gulleygrenhouse.com), James Greenhouses (www.jamesgreenhouses.com), and Walters Gardens (www.waltersgardens.com).