Gaillardia aristata ‘Arizona Sun’

April 26, 2005 - 11:04

Compact, floriferous and drought tolerant, this gaillardia has a bright future.

This fairly new gaillardia has been catching the attention of growers, landscapers and gardeners alike. With its compact habit, reaching only 8-10 inches tall by 10-12 inches wide, and its continuous bloom of 3-inch red and yellow flowers, this gaillardia is well suited for pot-production and mixed containers. ‘Arizona Sun’ produces masses of orange-red blooms surrounded by a ring of rich flame yellow from June-September. Even the spent blooms look attractive as they develop into attractive tufts of seed.

The common name, blanket flower, came about since the striking three-colored flowers of gaillardias resemble the colors commonly found in Indian blankets. Gaillardia aristata is native to the American plains and once established, becomes heat and drought tolerant. It thrives in full sun and can be produced throughout the country in USDA Hardiness Zones 2-10 and AHS Heat Zones 12-1.

With its desirable characteristics and strong performance, ‘Arizona Sun’ is winning numerous awards and accolades. It has most recently been selected the winner of the 2005 All-American Selections Flower Award and the Fleuroselect 2005 Gold Medal Award. With its ease of production and first-year flowering, it is likely to win a spot in the production schedules of growers across the country.

Propagation

‘Arizona Sun’ can easily be started from seed. Most greenhouses sow the seed in 288- or 200-cell plug trays filled with a growing medium that provides both good aeration and water-holding capacity. The seed should not be covered at sowing, as light is required for germination. Germination will occur in 5-10 days at temperatures between 70 and 75º F. Starting gaillardias inside a germination chamber will increase both the germination rate and percent germination, while decreasing the time necessary for all of the seeds to sprout. During the germination process it is important to keep the growing media uniformly moist but not wet. Once germinated, gaillardia can be grown with temperatures of 65-70° F. At these temperatures, ‘Arizona Sun’ will finish the plug stage in approximately 5-7 weeks.

Production

Typically, ‘Arizona Sun’ is produced in quart to 1-gal. containers. For best performance, plant one plug liner into the smaller containers and multiple plugs into the larger pots. The number of plugs to plant into 1-gal. containers depends on the size of the starting material and the preferences of the grower. When using a 220-cell plug, the grower might wish to plant three plugs per 1-gal. to fill out the pot quickly and uniformly. If 72-cell plugs are used, growers often plant either one or two plugs per 1-gal. pot; both methods are acceptable and commonly practiced. One-gallon containers with two 72-cell plugs fill out the pot quicker (approximately two weeks earlier), and due to the fullness of the pot, ‘Arizona Sun’ will produce more blooms and may be perceived as having a higher quality.

‘Arizona Sun’ performs well when transplanted into a good quality, well-drained peat- or bark-based growing medium. The pH of the media should be maintained between 5.8 and 6.8. Gaillardias are light to moderate feeders and grow well under constant liquid fertilizer programs with rates of 50-100 ppm nitrates with each watering or 150-200 ppm at every other watering. Growers using controlled-release fertilizers get the best results by incorporating fertilizer at a rate equivalent to 1 lb. of nitrogen per yard of growing medium. For example, if the time-release fertilizer formulation is 19-6-12, meaning it contains 19 percent nitrogen, the grower would need to incorporate 5.3 lbs. of this product per yard of media to obtain 1 lb. of elemental nitrogen (5.3 lbs. product x 19 percent = 1 lb. nitrogen). Time-release fertilizers can also be used by topdressing at the medium recommended rates.

‘Arizona Sun’ requires an average amount of irrigation, with a preference towards being on the dry side. It does not tolerate extremely wet conditions. Plants with weak stems and growth are often the result of excessive moisture and/or low light levels. Keeping them on the dry side will promote stronger stems and growth. I recommend, when watering is required, to water thoroughly, and allow the substrate to dry slightly between waterings.

Aphids are the primary insect pest of gaillardia. Other potential insect pests include caterpillars, leafhoppers, slugs, spider mites and thrips. Under various circumstances, gaillardias may be attacked by various plant pathogens: aster yellows, bacterial leaf spots and wilts, powdery mildew, rust, septoria and smut. Usually these diseases are not detrimental. As mentioned earlier, gaillardias do best when grown slightly dry. If produced under overly wet conditions, root and crown roots such as Pythium or Phytopthora are more likely to occur. With good watering practices, adequate plant spacing and plenty of air circulation, the occurrence of most diseases can almost be negated.

Usually, when grown with adequate spacing and proper growing conditions, it is not necessary to apply chemical growth regulators. If growth control is necessary, B-Nine (Crompton Crop Protection), Bonzi (Syngenta Professional Products), Sumagic (Valent USA Corp.) and the tank mix of B-Nine + Bonzi have all been effective at controlling the height of Gaillardia aristata.

Forcing

One of the most desirable characteristics of ‘Arizona Sun’ is its ability to bloom profusely the first year from seed. Providing a cold period is not necessary, as ‘Arizona Sun’ does not require vernalization for flowering. It is a long-day plant and grows best when produced under long-day conditions (day length longer than 14 hours) with high light levels. When the day length is naturally short, long-day conditions can be created by providing photoperiods (day length) of 16 hours. You can do this one of two ways: by extending the day if necessary or by using a 4-hour night interruption during the middle of the night, providing a minimum of 10 foot-candles of light at plant level.

Depending on the time of the year, production temperatures and size of the starter material, ‘Arizona Sun’ can generally be grown to a finished size in as little as 7-8 weeks. It is recommended to force gaillardias with temperatures ranging from 60-70º F. ‘Arizona Sun’ grown at 65º F will take seven weeks to reach flowering, while plants grown at 60º F will flower in nine weeks. To optimize plant development and produce high-quality plants, I recommend growers force gaillardias under high light levels with temperatures of 65-68º F.

Availability

‘Arizona Sun’ is available to the industry as a seed, plug or finished container. The seed is supplied by Ernst Benary of America and is available through many seed distributors. Plugs can be acquired from many perennial plug producers or plant brokers. Finished containers may be purchased from many reputable companies across the country.

About The Author

Paul Pilon is head grower at Sawyer Nursery, Hudsonville, Mich. He can be reached by E-mail at paul@perennial-solutions.com.

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