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perennial solutions nudicaule ‘Garden Gnome’

Gardeners and retailers alike have been warming up the Iceland ’s appeal in recent years. With its undeniable fl ower power, compact habit and ease of production, ‘Garden Gnome’ is quickly gaining popularity.

he Iceland poppy is an in fall plantings, which deliver Propagation By Paul Pilon attractive, delicate, cool- spectacular displays of color during ‘Garden Gnome’ is easily season perennial pro- the early spring. Iceland propagated from seed, which is duced by growers for are relatively easy to produce and available from Benary Seed. Ice- spring programs. It has are commonly marketed alongside land poppies are commonly sown Tbeen largely underused in the past bedding . in a variety of container sizes and is becoming increasingly pop- ‘Garden Gnome’ is a popular from small 288-cell plug trays to ular in recent years. The Iceland of Iceland poppies that is directly sowing them in 3-inch or poppy is a short-lived perennial widely grown in greenhouses for larger containers, multiple sowing in the North, but it is grown as an early sales. It produces compact, in both instances. Light is required annual in the South because it does low-growing rosettes of gray- for germination; do not cover the not tolerate the extreme summer green-lobed foliage reaching 4-6 seed with germination mix or heat of southern locations. Despite inches tall. It produces attractive vermiculite after sowing. Moisten its seemingly fragile nature, many 2-inch fl owers in the early spring the seed fl ats and move them into landscapers use Papaver nudicaule atop strong, upright, 9- to 12-inch a warm environment, where the hairy stems and continues to bloom temperatures can be maintained into the early summer. ‘Garden at 62-68° F for germination. Keep Gnome’ has great fl ower power: It the media slightly moist but not produces masses of blooms of var- wet during germination. It is best ious colors such as orange, scarlet, to geminate them in a chamber yellow and white (each color is with uniform moisture levels and available individually). Although temperatures. Using a germina- the most impressive display of tion chamber will also increase color occurs in the early spring, it both the germination rate and reblooms well into the summer in percent germination. most locations. The seeds should be germinated Papaver nudicaule belongs to the within fi ve to 10 days of sowing. family, which is native Once germinated, they can be to sub-Arctic regions of Asia and grown at temperatures of 60-64° North America. ‘Garden Gnome’ F. Following germination, reduce is commonly used in containers, the moisture levels somewhat, patio pots and in small mass or allowing the growing medium to border plantings, but Iceland pop- dry out slightly before watering pies can also be used as cut fl owers. to help promote rooting. Fertil- Papaver nudicaule performs well izers are usually applied once the across much of USDA Hardiness true leaves are present, applying Zones 2 to 7 and AHS Heat Zones 9 100-ppm nitrogen every third irri- to 2. As mentioned above, they are gation or 50 ppm with every irri- cool-season perennials and per- gation, using a balanced, water- form best when grown under these soluble source. When the plugs are conditions; they tend to struggle grown at 64° F, they are usually and may perish under extreme heat ready for transplanting in eight to or during extended dry periods. 10 weeks. ➧ ‘Garden Gnome’ produces masses of blooms of many eye-catching hues. (Photo: Benary)

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Production medium of the pot should be even them moist, but not consistently ‘Garden Gnome’ is often pro- with the top of the plug. Iceland wet. When irrigation is necessary, duced in 1-gallon or smaller-sized poppies perform best when grown I recommend watering thoroughly containers. Growers commonly in a moist, well-drained medium then allowing the soil to dry slightly use a single plug transplanted into with a slightly acidic pH: 5.8-6.4. between waterings. small container sizes and two plugs They require an average amount of They are light to moderate when larger sizes are being grown. irrigation and do not tolerate really feeders; providing moderate to After transplanting, the growing wet or overly dry conditions. Keep high fertility levels can cause them

This cultivar boasts attractive 2-inch fl owers atop hairy stems. (Photo: C. Raker & Sons)

to appear lush and leafy and may delay fl owering. Growers com- monly deliver nutrients using either a constant liquid fertilization program, feeding at rates of 75- to 100-ppm nitrates, or a controlled- release fertilizer incorporated at a rate equivalent to ¾ to 1 pound of nitrogen per yard of growing medium. In the spring, it is benefi - cial to fertilize with water-soluble fertilizers containing potassium that provides a 1:1 nitrogen to potassium ratio (i.e., as delivered with 15-0-15 or 17-2-17 formula- tions). Poppies are also prone to both magnesium and iron defi cien- cies, both of which appear as inter- veinal chlorosis. To overcome these defi ciencies, it may be necessary to drench with magnesium sulfate (Epsom salt) or iron chelate. With their compact growth habit, it is usually not necessary to control the height. Papaver growth can often be controlled by providing adequate spacing between the plants. It may be neces- sary, although not common, to use chemical plant growth regulators to control the growth of Iceland pop- pies. In the northern parts of the country, I recommend applying paclobutrazol (Bonzi, Paczol or Pic- colo) or the tank mix of daminozide (B-Nine or Dazide) at 2,000 ppm plus uniconazole (Concise or Sumagic) at 3 ppm. Applying one to two applica- tions seven days apart should pro- vide adequate height control.

Insects and Diseases Aphids, leafhoppers, leafminers, spider mites and thrips commonly feed on papaver. Of these insects, aphids are the most problematic. Preventive control measures are not needed; the presence of aphids (and other pests) can be detected through routine scouting, and, if necessary, control measures can be implemented.

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There are a number of disease is available to the industry as seeds, ppandl.net) and several reputable Guide to Perennial Production. He organisms known to attack pop- plugs or fi nished containers. The plant brokers. GPN can be reached at (616) 366-8588 pies, including anthracnose, bacte- seed is supplied by Benary Seed or [email protected]. rial blights, downy mildew, fungal (www.benary.com) and is available Paul Pilon is a horticultural con- leaf spots, root rots (Pythium and through many seed distributors. sultant, owner of Perennial Solu- LearnMore Rhizoctonia) and Verticillium. Plugs can be acquired from C. tions Consulting (www.perennial- For more information related to this article, go to Similar to controlling insects, Raker & Sons, Inc. (www.raker. solutions.com), and author of www.gpnmag.com/lm.cfm/gp090807 these diseases are often not prob- com), Pacifi c Plug & Liner (www. Perennial Solutions: A Grower’s lematic for growers. Early signs of these diseases can be detected with routine crop monitoring. To prevent the occurrence of these diseases, it is best to manage the environment by providing the proper plant spacing and ade- What happens to the quate air movement, controlling the humidity, monitoring the salt levels of the growing mix and pro- chemical that you spill viding proper irrigation practices. Forcing between plants Papaver ‘Garden Gnome’ is easy to force into bloom and is most com- monly produced for early spring when drenching? sales. They will fl ower the fi rst year from seed, but produce more fl owers when they have been over- wintered. ‘Garden Gnome’ does not have a cold requirement, but cold is benefi cial and will reduce the time to fl ower slightly, improve the uni- formity of bloom and increase the number of fl owers produced. Since they bloom so readily in the spring, it is benefi cial to transplant poppies into the fi nal container during the The early fall and allow them to root and bulk up prior to the cold treatment. CD2-Chemdose Iceland poppies are considered day- neutral plants but fl ower best when puts the chemical right in the pot. grown under high light levels in the early spring. This is accomplished by providing supplemental lighting, not photoperiodic lighting. The time to produce fl owering poppies after vernalization is a function temperature. ‘Garden Gnome’ grown at 60° F will take approximately eight weeks to reach fl owering, while plants grown at 56° F will fl ower in nine weeks. Producing them at cooler tempera- tures increases the time to fl ower but will improve the overall quality characteristics of the plant, such as Accurate Doses Easy to Program Portable the color intensity of the foliage and fl owers. To obtain full, fl owering plants for spring sales, it is benefi - cial to plant them during the late summer of the previous season. I Perfect for precise PGR and systemic insecticide applications. recommend transplanting plugs into the desired container during Call to learn how the CD2 can accurately dispense your chemicals. late August to early September, Integrated Plant Health bulking them up before winter, [email protected] over-wintering them and forcing www.dramm.com them to bloom in the early spring. 920.684.0227 Availability Papaver nudicaule ‘Garden Gnome’ Write in 711 www.gpnmag.com September 2008 GPN 49